21 research outputs found
The stellar halo of the Galaxy
Stellar halos may hold some of the best preserved fossils of the formation
history of galaxies. They are a natural product of the merging processes that
probably take place during the assembly of a galaxy, and hence may well be the
most ubiquitous component of galaxies, independently of their Hubble type. This
review focuses on our current understanding of the spatial structure, the
kinematics and chemistry of halo stars in the Milky Way. In recent years, we
have experienced a change in paradigm thanks to the discovery of large amounts
of substructure, especially in the outer halo. I discuss the implications of
the currently available observational constraints and fold them into several
possible formation scenarios. Unraveling the formation of the Galactic halo
will be possible in the near future through a combination of large wide field
photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes.
Full-resolution version available at
http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd
The American Astronomical Society, find out more The Institute of Physics, find out more The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances
We present part 2 of the 6th and final Data Release (DR6 or FDR) of the Radial Velocity Experiment (RAVE), a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A) and span the complete time frame from the start of RAVE observations on 12 April 2003 to their completion on 4 April 2013. In the second of two publications, we present the data products derived from 518387 observations of 451783 unique stars using a suite of advanced reduction pipelines focussing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters (Teff, log(g), and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall [alpha/Fe] ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The RAVE DR6 catalogs are cross matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the RAVE Web site (http://rave-survey.org) or the Vizier database
Dynamics of Disks and Warps
This chapter reviews theoretical work on the stellar dynamics of galaxy
disks. All the known collective global instabilities are identified, and their
mechanisms described in terms of local wave mechanics. A detailed discussion of
warps and other bending waves is also given. The structure of bars in galaxies,
and their effect on galaxy evolution, is now reasonably well understood, but
there is still no convincing explanation for their origin and frequency. Spiral
patterns have long presented a special challenge, and ideas and recent
developments are reviewed. Other topics include scattering of disk stars and
the survival of thin disks.Comment: Chapter accepted to appear in Planets, Stars and Stellar Systems, vol
5, ed G. Gilmore. 32 pages, 17 figures. Includes minor corrections made in
proofs. Uses emulateapj.st
Observations on the Gastric Mucosa of Rheumatic Patients before and after Ibuprofen Administration as Studied by the Pentagastrin Test, Endoscopy, and Light and Electron Microscopy
Nimesulide, a novel NSAID of the sulfonanilide class, inhibits PGE2 production by human chondrocytes without affecting proteoglycans synthesis
peer reviewe
Effect of nimesulide on the serum levels of hyaluronan and stromelysin-1 in patients with osteoarthritis: a pilot study
This prospective preliminary single-blind study was conducted in patients suffering from osteoarthritis (OA) and requiring non-steroidal anti-inflammatory drugs (NSAIDs) to determine to what extent nimesulide (200 mg/day) and ibuprofen (1200 mg/day) could induce significant changes in the serum levels of matrix metalloproteinase-3 (MMP-3), tissue inhibitor-1 of MMPs (TIMP-1), hyaluronan (HA) and YKL-40 after a therapeutic time period of 28 days. The four biochemical parameters were assessed by using immunoassays. Nimesulide significantly reduced the serum levels of both HA and MMP-3, whereas ibuprofen increased moderately but significantly the serum concentrations of MMP-3 and had no effect on the serum concentrations of HA. The two NSAIDs were unable to change the serum levels of both TIMP-1 and YKL-40. These results suggest that nimesulide might have a favourable effect on the metabolism of OA joints