186 research outputs found
Safety of measles, mumps, and rubella vaccine in egg allergy: in vivo and in vitro management
Background: Egg allergy is the second most prevalent form of food allergy in childhood. In spite of the evidence accumulated, inoculating egg allergy children with attenuated vaccines grown on chick embryo cell cultures, such as the measles, mumps, and rubella (MMR) vaccine, is regarded (erroneously) as potentially dangerous or even anaphylactogenic, by many. An issue perceived as particularly conflicting also by Health Professionals. Case presentation: A 15-year-old boy, with a history of severe egg allergy in early infancy, who was still sensitized to egg allergens, including baked egg, had never received MMR vaccination, in fear of possible anaphylaxis, in spite of the fact that this vaccination is mandatory in the first year of life, in Italy. Because of that, he was not allowed to attend school, longer, and was referred to us in order to assess the potential risk of MMR vaccination. Upon thorough allergologic workup, sensitization to MMR vaccine components was excluded by an in vivo approach, consisting in skin prick tests, intradermal tests, and subcutaneous injection test, corroborated by vaccine-specific B-lymphocyte proliferation assay, ex vivo. T-cell proliferation in response to MMR vaccine was also excluded. Eventually, the boy was inoculated with MMR vaccine and was readmitted to school. Conclusions: The diagnostic strategy adopted appears feasible and easy-to-perform and may be adopted in controversial cases (as the one reported), characterized by previous severe allergic reactions to egg. The B-lymphocyte proliferation assay we developed may represent a useful and reliable tool not only in research but also in clinical practice
Self-administered Meditation Application Intervention for Cancer Patients With Psychosocial Distress: A Pilot Study
BACKGROUND: We explored the use of a novel smart phone-based application (APP) for delivery and monitoring of meditation to treat mood symptoms experienced by cancer patients.
METHODS: We assessed the feasibility of using a meditation delivery and tracking APP over 2-weeks and its impact on cancer patients\u27 self-reported anxiety and depression. Outpatients reporting depression and/or anxiety were recruited and randomized to the APP or waitlist control group. Assessments included an expectancy scale, exit survey, mood rating before and after each meditation, and the Edmonton Symptom Assessment Scale (ESAS-FS), Hospital Anxiety and Depression Scale (HADS), and Pittsburgh Sleep Quality Index (PSQI) at baseline and after 2-weeks. The primary aim was to assess feasibility; secondary aims included satisfaction with the APP, association between meditation frequency and length with self-reported symptoms, and change in symptom measures (symptoms, anxiety, depression, and sleep).
RESULTS: Our study included 35 participants (17 meditation group; 18 controls) who were primarily female (94%) with breast cancer (60%). The 61% enrollment rate and 71% adherence rate met pre-specified feasibility criteria. Most meditation group participants described the APP as Useful to Very Useful and would Probably or Definitely recommend its use. Mixed model analysis revealed a statistically significant association between meditation length (5, 10, or 15 minutes) and change in anxiety, with 15-minute sessions associated with greater reductions in anxiety. In the exit survey, more meditation group vs. control group participants reported improved focus, mood, and sleep. Study groups differed significantly by ESAS fatigue score change; the meditation group decreased a median of 1.5 pts (IQR 2.5) and the control group increased a median of 0.5 points (IQR 2). The meditation group, but not the control group, experienced statistically significant improvement in ESAS fatigue, depression, anxiety, appetite, and physical, psychological, and global distress. Change in PSQI and HADS anxiety and depression scores did not reveal any statistically significant between-group differences.
CONCLUSIONS: This pilot study demonstrated the feasibility and acceptability of a meditation APP for cancer patients. Meditation APP users reported improvement in several measures of symptom distress. Future studies should explore ways to enhance the APP\u27s usability and clinical benefit
<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties
Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7.
Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release.
Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue.
Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7.
Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data
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Gaia Data Release 2: The celestial reference frame (Gaia -CRF2)
Context. The second release of Gaia data (Gaia DR2) contains the astrometric parameters for more than half a million quasars. This set defines a kinematically non-rotating reference frame in the optical domain. A subset of these quasars have accurate VLBI positions that allow the axes of the reference frame to be aligned with the International Celestial Reference System (ICRF) radio frame. Aims. We describe the astrometric and photometric properties of the quasars that were selected to represent the celestial reference frame of Gaia DR2 (Gaia-CRF2), and to compare the optical and radio positions for sources with accurate VLBI positions. Methods. Descriptive statistics are used to characterise the overall properties of the quasar sample. Residual rotation and orientation errors and large-scale systematics are quantified by means of expansions in vector spherical harmonics. Positional differences are calculated relative to a prototype version of the forthcoming ICRF3. Results. Gaia-CRF2 consists of the positions of a sample of 556 869 sources in Gaia DR2, obtained from a positional cross-match with the ICRF3-prototype and AllWISE AGN catalogues. The sample constitutes a clean, dense, and homogeneous set of extragalactic point sources in the magnitude range G ≈ 16 to 21 mag with accurately known optical positions. The median positional uncertainty is 0.12 mas for G < 18 mag and 0.5 mas at G = mag. Large-scale systematics are estimated to be in the range 20 to 30 μas. The accuracy claims are supported by the parallaxes and proper motions of the quasars in Gaia DR2. The optical positions for a subset of 2820 sources in common with the ICRF3-prototype show very good overall agreement with the radio positions, but several tens of sources have significantly discrepant positions. Conclusions. Based on less than 40% of the data expected from the nominal Gaia mission, Gaia-CRF2 is the first realisation of a non-rotating global optical reference frame that meets the ICRS prescriptions, meaning that it is built only on extragalactic sources. Its accuracy matches the current radio frame of the ICRF, but the density of sources in all parts of the sky is much higher, except along the Galactic equator
Gaia Data Release 1: Open cluster astrometry: Performance, limitations, and future prospects
Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric
Solution (TGAS). This is a subset of about 2 million stars for which, besides
the position and photometry, the proper motion and parallax are calculated
using Hipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We
investigate the scientific potential and limitations of the TGAS component by
means of the astrometric data for open clusters. Methods. Mean cluster parallax
and proper motion values are derived taking into account the error correlations
within the astrometric solutions for individual stars, an estimate of the
internal velocity dispersion in the cluster, and, where relevant, the effects
of the depth of the cluster along the line of sight. Internal consistency of
the TGAS data is assessed. Results. Values given for standard uncertainties are
still inaccurate and may lead to unrealistic unit-weight standard deviations of
least squares solutions for cluster parameters. Reconstructed mean cluster
parallax and proper motion values are generally in very good agreement with
earlier Hipparcos-based determination, although the Gaia mean parallax for the
Pleiades is a significant exception. We have no current explanation for that
discrepancy. Most clusters are observed to extend to nearly 15 pc from the
cluster centre, and it will be up to future Gaia releases to establish whether
those potential cluster-member stars are still dynamically bound to the
clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters
far beyond their more easily visible cores, and can provide membership
assessments based on proper motions and parallaxes. A combined HR diagram shows
the same features as observed before using the Hipparcos data, with clearly
increased luminosities for older A and F dwarfs
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Gaia Data Release 1: Summary of the astrometric, photometric, and survey properties
At about 1000 days after the launch of Gaia we present the first Gaia data
release, Gaia DR1, consisting of astrometry and photometry for over 1 billion
sources brighter than magnitude 20.7. We summarize Gaia DR1 and provide
illustrations of the scientific quality of the data, followed by a discussion
of the limitations due to the preliminary nature of this release. Gaia DR1
consists of: a primary astrometric data set which contains the positions,
parallaxes, and mean proper motions for about 2 million of the brightest stars
in common with the Hipparcos and Tycho-2 catalogues and a secondary astrometric
data set containing the positions for an additional 1.1 billion sources. The
second component is the photometric data set,consisting of mean G-band
magnitudes for all sources. The G-band light curves and the characteristics of
~3000 Cepheid and RR Lyrae stars, observed at high cadence around the south
ecliptic pole, form the third component. For the primary astrometric data set
the typical uncertainty is about 0.3 mas for the positions and parallaxes, and
about 1 mas/yr for the proper motions. A systematic component of ~0.3 mas
should be added to the parallax uncertainties. For the subset of ~94000
Hipparcos stars in the primary data set, the proper motions are much more
precise at about 0.06 mas/yr. For the secondary astrometric data set, the
typical uncertainty of the positions is ~10 mas. The median uncertainties on
the mean G-band magnitudes range from the mmag level to ~0.03 mag over the
magnitude range 5 to 20.7. Gaia DR1 represents a major advance in the mapping
of the heavens and the availability of basic stellar data that underpin
observational astrophysics. Nevertheless, the very preliminary nature of this
first Gaia data release does lead to a number of important limitations to the
data quality which should be carefully considered before drawing conclusions
from the data
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Observational hertzsprung-russell diagrams
We highlight the power of the Gaia DR2 in studying many fine structures of
the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different
HRDs, depending in particular on stellar population selections. We do not aim
here for completeness in terms of types of stars or stellar evolutionary
aspects. Instead, we have chosen several illustrative examples. We describe
some of the selections that can be made in Gaia DR2 to highlight the main
structures of the Gaia HRDs. We select both field and cluster (open and
globular) stars, compare the observations with previous classifications and
with stellar evolutionary tracks, and we present variations of the Gaia HRD
with age, metallicity, and kinematics. Late stages of stellar evolution such as
hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also
analysed, as well as low-mass brown dwarf objects. The Gaia HRDs are
unprecedented in both precision and coverage of the various Milky Way stellar
populations and stellar evolutionary phases. Many fine structures of the HRDs
are presented. The clear split of the white dwarf sequence into hydrogen and
helium white dwarfs is presented for the first time in an HRD. The relation
between kinematics and the HRD is nicely illustrated. Two different populations
in a classical kinematic selection of the halo are unambiguously identified in
the HRD. Membership and mean parameters for a selected list of open clusters
are provided. They allow drawing very detailed cluster sequences, highlighting
fine structures, and providing extremely precise empirical isochrones that will
lead to more insight in stellar physics. Gaia DR2 demonstrates the potential of
combining precise astrometry and photometry for large samples for studies in
stellar evolution and stellar population and opens an entire new area for
HRD-based studies
Gaia Early Data Release 3 Acceleration of the Solar System from Gaia astrometry
Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate. Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 +/- 0.16) x 10(-10) m s(-2) (or 7.33 +/- 0.51 km s(-1) Myr-1) towards alpha = 269.1 degrees +/- 5.4 degrees, delta = -31.6 degrees +/- 4.1 degrees, corresponding to a proper motion amplitude of 5.05 +/- 0.35 mu as yr(-1). This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 mu as yr(-1).Peer reviewe
Gaia Data Release 2 Mapping the Milky Way disc kinematics
Context. The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources as well as line-of-sight velocities for 7.2 million stars brighter than G(RVS) = 12 mag. Both samples provide a full sky coverage. Aims. To illustrate the potential of Gaia DR2, we provide a first look at the kinematics of the Milky Way disc, within a radius of several kiloparsecs around the Sun. Methods. We benefit for the first time from a sample of 6.4 million F-G-K stars with full 6D phase-space coordinates, precise parallaxes (sigma((omega) over bar)/(omega) over bar Results. Gaia DR2 allows us to draw 3D maps of the Galactocentric median velocities and velocity dispersions with unprecedented accuracy, precision, and spatial resolution. The maps show the complexity and richness of the velocity field of the galactic disc. We observe streaming motions in all the components of the velocities as well as patterns in the velocity dispersions. For example, we confirm the previously reported negative and positive galactocentric radial velocity gradients in the inner and outer disc, respectively. Here, we see them as part of a non-axisymmetric kinematic oscillation, and we map its azimuthal and vertical behaviour. We also witness a new global arrangement of stars in the velocity plane of the solar neighbourhood and in distant regions in which stars are organised in thin substructures with the shape of circular arches that are oriented approximately along the horizontal direction in the U - V plane. Moreover, in distant regions, we see variations in the velocity substructures more clearly than ever before, in particular, variations in the velocity of the Hercules stream. Conclusions. Gaia DR2 provides the largest existing full 6D phase-space coordinates catalogue. It also vastly increases the number of available distances and transverse velocities with respect to Gaia DR1. Gaia DR2 offers a great wealth of information on the Milky Way and reveals clear non-axisymmetric kinematic signatures within the Galactic disc, for instance. It is now up to the astronomical community to explore its full potential.Peer reviewe
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Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)
Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution
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