124,912 research outputs found
ICF Core Sets: how to specify impairment and function in systemic lupus erythematosus
No full textThe World Health Organization’s International Classification of Function (ICF) is a tool to characterize and illuminate better the full of array of problems a patient faces when affected by disease. Specifying these problems is a particular challenge in a disease like systemic lupus erythematosus (SLE) because of the wide variety in organ systems involved, its variable activity and severity, and considerable ethnic and local differences. The authors of this manuscript believe, however, that a broader understanding will prove essential for optimal patient care, and that there is sufficient experience now in defining ICF Core Sets to successfully complete core sets for SLE. Therefore, we will embark on an international project for developing ICF Core Sets for SLE, which we here delineate. This development will include two versions: 1) The Brief ICF Core Set for SLE will be a very focused list of categories essential for SLE clinical trials; and 2) The Comprehensive ICF Core Set will be much broader and useful for guiding multidisciplinary assessment in patients with SLE. Both Core Sets will be developed in a formal decision-making and consensus process of health professionals integrating evidence gathered from preliminary studies. The final definition of the Core Sets will occur at a consensus conference which will integrate: i) a systematic review of the literature regarding the outcome measures used in clinical trials and selected observational studies; ii) focus groups or semi-structured interviews with SLE patients; iii) a Delphi exercise with world wide involvement of experts; and iv) the evidence from empirical studies. The development of these SLE ICF Core Sets is designed to be an inclusive, open, worldwide process. We therefore invite both SLE clinical experts and SLE patients to participate actively
Synthetic spectrophotometry for C-rich giants (Aringer+, 2009)
No full textThe following bolometric correction tables have been calculated from
COMA07/SPHREAD03 spectra based on COMARCS04 hydrostatic models.
Reddening due to circumstellar dust is not included. Each of the 36
tables contains a photometric system including different filters. If a
certain filter curve is not covered by the synthetic spectra (below 4444
and above 250000A) a value of -999999 is listed for the bolometric
correction. Details concerning the photometric systems are given in
Marigo, P., Girardi, L., Bressan, A., et al., 2008A&A...482..883M
and in http://stev.oapd.inaf.it/~lgirardi/cmd_2.1/photsys.html
Evolutionary Models for AGB Stars in the Magellanic Clouds
No full textAGB stars in the Magellanic Clouds (MCs) are the most robust calibrators for the modelling of this phase, thanks to the large collection of high-quality data (photometry, chemistry, pulsation properties, mass-loss, dust features, etc.) presently available. As part of an ambitious project aimed at substantially improving the performance of AGB synthetic models for the MCs, we revise the stellar models for the MCs. Particular attention is put on the chemical composition, in terms of both the initial mixture at the epoch of star formation, and the subsequent changes in surface abundances during the TP-AGB phase. We derive the initial chemical composition from recent spectroscopic analyses, which indicate that the MCs present non-scaled-solar ratios for key species such as C, N, O, and α-elements. The depression of oxygen ([O/Fe] ̃ -0.2) and of nitrogen ([N/Fe] ̃ -1.0), and the rather low metallicity (Z ̃ 0.005 instead of the standard Z ̃ 0.008) are among the most striking features. Evolutionary tracks are calculated with a new updated version
of the Padova stellar evolution code, from the pre-main sequence phase up to the beginning of the TP-AGB phase, which is then decribed by means
of our synthetic model. The changes in the surface abudances (due to the third dredge-up and hot-bottom burning) are consistenly coupled to variations in the low-temperature opacities that are computed, for the first time, on-the-fly with the AESOPUS code (Marigo & Aringer 2009). Here I decribe the new sets of stellar models, with particular emphasis on the evolution of S-type and C-type stars, as well of more massive AGB stars experiencing hot-bottom burning
Supplemental material for Early symptoms of systemic lupus erythematosus (SLE) recalled by 339 SLE patients
No full textSupplemental material for Early symptoms of systemic lupus erythematosus (SLE) recalled by 339 SLE patients by N Leuchten, B Milke, B Winkler-Rohlfing, D Daikh, T Dörner, S R Johnson and M Aringer in Lupus</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Low-temperature gas opacity AESOPUS: a versatile and quick computational tool
No full textWe introduce a new tool - ÆSOPUS: Accurate Equation of State and OPacity Utility Software - for computing the equation of state and the Rosseland mean (RM) opacities of matter in the ideal gas phase. Results are given as a function of one pair of state variables, (i.e. temperature T in the range 3.2 ≤ log(T) ≤ 4.5, and parameter R= ρ/(T/106 K)3 in the range -8 ≤ log(R) ≤ 1), and arbitrary chemical mixture. The chemistry is presently solved for about 800 species, consisting of almost 300 atomic and 500 molecular species. The gas opacities account for many continuum and discrete sources, including atomic opacities, molecular absorption bands, and collision-induced absorption. Several tests made on ÆSOPUS have proved that the new opacity tool is accurate in the results, flexible in the management of the input prescriptions, and agile in terms of computational time requirement. Purpose of this work is to greatly expand the public availability of Rosseland mean opacity data in the low-temperature regime. We set up a web-interface (http://stev.oapd.inaf.it/aesopus) which enables the user to compute and shortly retrieve RM opacity tables according to his/her specific needs, allowing a full degree of freedom in specifying the chemical composition of the gas. As discussed in the paper, useful applications may regard, for instance, RM opacities of gas mixtures with i) scaled-solar abundances of metals, choosing among various solar mixture compilations available in the literature; ii) varying CNO abundances, suitable for evolutionary models of red and asymptotic giant branch stars and massive stars in the Wolf-Rayet stages; iii) various degrees of enhancement in α-elements, and C-N, O-Na, and Mg-Al abundance anti-correlations, necessary to properly describe the properties of stars in early-type galaxies and Galactic globular clusters; iv) zero-metal abundances appropriate for studies of gas opacity in primordial conditions
Synthetic photometry for M and K giants and stellar evolution: hydrostatic dust-free model atmospheres and chemical abundances
No full textBased on a grid of hydrostatic spherical COMARCS models for cool stars, we have calculated observable properties of these objects, which will be mainly used in combination with stellar evolution tracks and population synthesis tools. The high-resolution opacity sampling and low-resolution convolved spectra as well as bolometric corrections for a large number of filter systems are made electronically available. We exploit those data to study the effect of mass, C/O ratio and nitrogen abundance on the photometry of K and M giants. Depending on effective temperature, surface gravity and the chosen wavelength ranges, variations of the investigated parameters cause very weak to moderate and, in the case of C/O values close to 1, even strong shifts of the colours. For the usage with stellar evolution calculations, they will be treated as correction factors applied to the results of an interpolation in the main quantities. When we compare the synthetic photometry to observed relations and to data from the Galactic bulge, we find in general a good agreement. Deviations appear for the coolest giants showing pulsations, mass-loss and dust shells, which cannot be described by hydrostatic models
An extensive grid of DARWIN models for M-Type AGB stars: I. Mass-loss rates and other properties of dust-driven winds
No full textContext. The stellar winds of asymptotic giant branch (AGB) stars are commonly attributed to radiation pressure on dust grains, formed in the wake of shock waves that arise in the stellar atmospheres. The mass loss due to these outflows is substantial, and modelling the dynamical properties of the winds is essential both for studies of individual stars and for understanding the evolution of stellar populations with low to intermediate mass.
Aims: The purpose of this work is to present an extensive grid of dynamical atmosphere and wind models for M-type AGB stars, covering a wide range of relevant stellar parameters.
Methods: We used the DARWIN code, which includes frequency-dependent radiation-hydrodynamics and a time-dependent description of dust condensation and evaporation, to simulate the dynamical atmosphere. The wind-driving mechanism is photon scattering on submicron-sized Mg2SiO4 grains. The grid consists of 4000 models, with luminosities from L⋆ = 890 L☉ to L⋆ = 40 000 L☉ and effective temperatures from 2200 to 3400 K. For the first time different current stellar masses are explored with M-type DARWIN models, ranging from 0.75 M☉ to 3 M☉. The modelling results are radial atmospheric structures, dynamical properties such as mass-loss rates and wind velocities, and dust properties (e.g. grain sizes, dust-to-gas ratios, and degree of condensed Si).
Results: We find that the mass-loss rates of the models correlate strongly with luminosity. They also correlate with the ratio L*/M*: increasing L*/M* by an order of magnitude increases the mass-loss rates by about three orders of magnitude, which may naturally create a superwind regime in evolution models. There is, however, no discernible trend of mass-loss rate with effective temperature, in contrast to what is found for C-type AGB stars. We also find that the mass-loss rates level off at luminosities higher than 14 000 L☉, and consequently at pulsation periods longer than 800 days. The final grain radii range from 0.25 to 0.6 μm. The amount of condensed Si is typically between 10 and 40%, with gas-to-dust mass ratios between 500 and 4000. The wind and dust characteristics produced by the DARWIN models and the input parameters of each model are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/626/A10
Lithium abundances of bulge RGB stars (Lebzelter+, 2012)
No full textThe table presents the coordinates (J2000) and J-, H-, and K-band magnitudes from the 2MASS catalogue, the radial velocities measured from the spectra, their estimated temperature and surface gravity log g,
general metal and lithium abundances for the Li-detected stars, as well
as a flag for foreground star candidates. The foreground star candidates
were selected by their proper motion in the SPM4 catalogue. All stars are located in a 25 arcmin diameter field centred on the Galactic coordinates (l,b)=(0,-10).
(1 data file)
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