544 research outputs found
Activation and Inactivation Kinetics of Torpedo californica Acetylcholine Receptor in Reconstituted Membranes
P>Background: To date no studies have compared generic health-related quality of life (HRQL) of food allergic patients from childhood to adulthood with that of the general population or patients with other chronic diseases. The aim of this study was to compare generic HRQL of food allergic patients with the general population and other diseases. Methods: Generic HRQL questionnaires (CHQ-CF87 and RAND-36) were completed by 79 children, 74 adolescents and 72 adults with food allergy. The generic HRQL scores were compared with scores from published studies on the general population and patients with asthma, irritable bowel syndrome (IBS), diabetes mellitus (DM) and rheumatoid arthritis (RA). Results: Food allergic children and adolescents reported fewer limitations in school work due to behavioural problems (P <0.013), but food allergic adolescents and adults reported more pain (P = 0.020), poorer overall health (P <0.001), more limitations in social activities (P <0.001) and less vitality (P = 0.002) than individuals from the general population. Food allergic patients reported poorer generic HRQL than patients with DM, but better generic HRQL than patients with RA, asthma and IBS. Conclusion: HRQL is impaired in food allergic adolescents and adults, compared to the general population, and it is intermediate in magnitude between DM and RA, asthma and IBS. Children show the least impact on generic HRQL from food allergy
The Gaia-ESO Survey: Chromospheric Emission, Accretion Properties, and Rotation in Velorum and Chamaeleon I
We use the fundamental parameters delivered by the GES consortium in the
first internal data release to select the members of Vel and Cha I
among the UVES and GIRAFFE spectroscopic observations. A total of 140
Vel members and 74 Cha I members were studied. We calculated stellar
luminosities through spectral energy distributions, while stellar masses were
derived by comparison with evolutionary tracks. The spectral subtraction of
low-activity and slowly rotating templates, which are rotationally broadened to
match the of the targets, enabled us to measure the equivalent widths
(EWs) and the fluxes in the H and H lines. The H line
was also used for identifying accreting objects and for evaluating the mass
accretion rate (). The distribution of for the
members of Vel displays a peak at about 10 km s with a tail
toward faster rotators. There is also some indication of a different
distribution for the members of its two kinematical populations. Only a handful
of stars in Vel display signatures of accretion, while many more
accretors were detected in the younger Cha~I. Accreting and active stars occupy
two different regions in a -flux diagram and we propose a
criterion for distinguishing them. We derive in the ranges
-yr and -yr
for Vel and Cha I accretors, respectively. We find less scatter in the
relation derived through the H EWs, when
compared to the H diagnostics, in agreement with other authors
The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge
We present the first results of the EMBLA survey (Extremely Metal-poor BuLge
stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge,
where the oldest stars should now preferentially reside. EMBLA utilises
SkyMapper photometry to pre-select metal-poor candidates, which are
subsequently confirmed using AAOmega spectroscopy. We describe the discovery
and analysis of four bulge giants with -2.72<=[Fe/H]<=-2.48, the lowest
metallicity bulge stars studied with high-resolution spectroscopy to date.
Using FLAMES/UVES spectra through the Gaia-ESO Survey we have derived
abundances of twelve elements. Given the uncertainties, we find a chemical
similarity between these bulge stars and halo stars of the same metallicity,
although the abundance scatter may be larger, with some of the stars showing
unusual [{\alpha}/Fe] ratios.Comment: 7 pages, 5 figures. Accepted for publication by MNRA
Micrometeoroid Events in LISA Pathfinder
The zodiacal dust complex, a population of dust and small particles that
pervades the Solar System, provides important insight into the formation and
dynamics of planets, comets, asteroids, and other bodies. Here we present a new
set of data obtained using a novel technique: direct measurements of momentum
transfer to a spacecraft from individual particle impacts. This technique is
made possible by the extreme precision of the instruments flown on the LISA
Pathfinder spacecraft, a technology demonstrator for a future space-based
gravitational wave observatory that operated near the first Sun-Earth Lagrange
point from early 2016 through Summer of 2017. Using a simple model of the
impacts and knowledge of the control system, we show that it is possible to
detect impacts and measure properties such as the transferred momentum (related
to the particle's mass and velocity), direction of travel, and location of
impact on the spacecraft. In this paper, we present the results of a systematic
search for impacts during 4348 hours of Pathfinder data. We report a total of
54 candidates with momenta ranging from 0.2 to
230. We furthermore make a comparison of these candidates
with models of micrometeoroid populations in the inner solar system including
those resulting from Jupiter-family comets, Oort-cloud comets, Hailey-type
comets, and Asteroids. We find that our measured population is consistent with
a population dominated by Jupiter-family comets with some evidence for a
smaller contribution from Hailey-type comets. This is in agreement with
consensus models of the zodiacal dust complex in the momentum range sampled by
LISA Pathfinder.Comment: 22 pages, 14 figures, accepted in Ap
The Gaia -ESO Survey : Empirical determination of the precision of stellar radial velocities and projected rotation velocities
Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (v sin i) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods. We present an analysis to empirically quantify the size and distribution of uncertainties in RV and v sin i using spectra from repeated exposures of the same stars. Results. We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and v sin i, that the uncertainties become larger with increasing photospheric temperature, but that the dependence on stellar gravity, metallicity and age is weak. The underlying uncertainty distributions have extended tails that are better represented by Student's t-distributions than by normal distributions. Conclusions. Parametrised results are provided, which enable estimates of the RV precision for almost all GES measurements, and estimates of the v sin i precision for stars in young clusters, as a function of S/N, v sin i and stellar temperature. The precision of individual high S/N GES RV measurements is 0.22-0.26 kms-1, dependent on instrumental configuration.Peer reviewedFinal Accepted Versio
How does dose impact on the severity of food-induced allergic reactions, and can this improve risk assessment for allergenic foods?
Funding informationThis work was conducted by an expert group of the European branch of the International Life Sciences Institute, ILSI Europe. This publication was coordinated by the Food Allergy Task Force. Industry members of this task force are listed on the ILSI Europe website at http://ilsi.eu/task-forces/food-safety/food-allergy/. Experts are not paid for the time spent on this work; however, the nonindustry members within the expert group were offered support for travel and accommodation costs from the Food Allergy Task Force to attend meetings to discuss the manuscript and a small compensatory sum (honorarium) with the option to decline. The expert group carried out the work, that is collecting/analysing data/information and writing the scientific paper separate to other activities of the task force. The research reported is the result of a scientific evaluation in line with ILSI Europe's framework to provide a precompetitive setting for public‐private partnership. ILSI Europe facilitated scientific meetings and coordinated the overall project management and administrative tasks relating to the completion of this work. For further information about ILSI Europe, please email [email protected] or call +3227710014. The opinions expressed herein and the conclusions of this publication are those of the authors and do not necessarily represent the views of ILSI Europe nor those of its member companies or any regulatory authority
Identification and mitigation of narrow spectral artifacts that degrade searches for persistent gravitational waves in the first two observing runs of Advanced LIGO
Searches are under way in Advanced LIGO and Virgo data for persistent gravitational waves from continuous sources, e.g. rapidly rotating galactic neutron stars, and stochastic sources, e.g. relic gravitational waves from the Big Bang or superposition of distant astrophysical events such as mergers of black holes or neutron stars. These searches can be degraded by the presence of narrow spectral artifacts (lines) due to instrumental or environmental disturbances. We describe a variety of methods used for finding, identifying and mitigating these artifacts, illustrated with particular examples. Results are provided in the form of lists of line artifacts that can safely be treated as non-astrophysical. Such lists are used to improve the efficiencies and sensitivities of continuous and stochastic gravitational wave searches by allowing vetoes of false outliers and permitting data cleaning
The Gaia-ESO Survey : The analysis of high-resolution UVES spectra of FGK-type stars
Date of Acceptance: 01/09/2014Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 105 stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods. The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results. The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected Teff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55 K for Teff, 0.13 dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for Teff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex. Conclusions. The Gaia-ESO sample of high-resolution spectra of FGK-type stars will be among the largest of its kind analyzed in a homogeneous way. The extensive list of elemental abundances derived in these stars will enable significant advances in the areas of stellar evolution and Milky Way formation and evolution.Peer reviewe
The Gaia-ESO Survey: Spectroscopic-asteroseismic analysis of K2 stars in Gaia-ESO
The extensive stellar spectroscopic datasets that are available for studies
in Galactic Archeaology thanks to, for example, the Gaia-ESO Survey, now
benefit from having a significant number of targets that overlap with
asteroseismology projects such as Kepler, K2 and CoRoT. Combining the
measurements from spectroscopy and asteroseismology allows us to attain greater
accuracy with regard to the stellar parameters needed to characterise the
stellar populations of the Milky Way. The aim of this Gaia-ESO Survey special
project is to produce a catalogue of self-consistent stellar parameters by
combining measurements from high-resolution spectroscopy and precision
asteroseismology. We carried out an iterative analysis of 90 K2@Gaia-ESO red giants. The spectroscopic values of Teff were used as input in the seismic analysis to obtain log(g) values. The seismic estimates of log(g) were then used to re-determine the spectroscopic values of Teff and [Fe/H]. Only one iteration was required to obtain parameters that are in good agreement for both methods and thus, to obtain the final stellar parameters. A detailed analysis of outliers was carried out to ensure a robust determination of the parameters. The results were then combined with Gaia DR2 data to compare the seismic log(g) with a parallax-based log(g) and to investigate instances of variations in the velocity and possible binaries within the dataset. This analysis produced a high-quality catalogue of stellar parameters for 90 red giant stars observed by both K2 and Gaia-ESO that were determined through iterations between spectroscopy and asteroseismology. We compared the seismic gravities with those based on Gaia parallaxes to find an offset which is similar to other studies that have used asteroseismology. Our catalogue also includes spectroscopic chemical abundances and radial velocities, as well as indicators for possible binary detections
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