627 research outputs found
Cost-effectiveness of extended-release niacin/laropiprant added to a stable simvastatin dose in secondary prevention patients not at cholesterol goal in Germany
Coronary heart disease (CHD) remains the leading cause of death in Germany despite statin use to reduce low-density lipoprotein cholesterol (LDL-C) levels; improving lipids beyond LDL-C may further reduce cardiovascular risk. A fixed-dose combination of extended-release niacin (ERN) with laropiprant (LRPT) provides comprehensive lipid management. We adapted a decision-analytic model to evaluate the economic value (incremental cost-effectiveness ratio [ICER] in terms of costs per life-years gained [LYG]) of ERN/LRPT 2 g over a lifetime in secondary prevention patients in a German setting. Two scenarios were modelled: (1) ERN/LRPT 2 g added to simvastatin 40 mg in patients not at LDL-C goal with simvastatin 40 mg; (2) adding ERN/LRPT 2 g compared with titration to simvastatin 40 mg in patients not at LDL-C goal with simvastatin 20 mg. In both scenarios, adding ERN/LRPT was cost-effective relative to simvastatin monotherapy at a commonly accepted threshold of €30,000 per LYG; ICERs for ERN/LRPT were €13,331 per LYG in scenario 1 and €17,684 per LYG in scenario 2. Subgroup analyses showed that ERN/LRPT was cost-effective in patients with or without diabetes, patients aged ≤65 or >65 years and patients with low baseline high-density lipoprotein cholesterol levels; ICERs ranged from €10,342 to €15,579 in scenario 1, and from €14,081 to €20,462 in scenario 2. In conclusion, comprehensive lipid management with ERN/LRPT 2 g is cost-effective in secondary prevention patients in Germany who have not achieved LDL-C goal with simvastatin monotherapy
Fast and Slow Rotators: The build-up of the Red Sequence
Using the unique dataset obtained within the course of the SAURON project, a
radically new view of the structure, dynamics and stellar populations of
early-type galaxies has emerged. We show that galaxies come in two broad
flavours (slow and fast rotators), depending on whether or not they exhibit
clear large-scale rotation, as indicated via a robust measure of the specific
angular momentum of baryons. This property is also linked with other physical
characteristics of early-type galaxies, such as: the presence of dynamically
decoupled cores, orbital structure and anisotropy, stellar populations and dark
matter content. I here report on the observed link between this baryonic
angular momentum and a mass sequence, and how this uniquely relates to the
building of the red sequence via dissipative/dissipationless mergers and
secular evolution.Comment: 4 pages, 1 figure. To appear in the Proceedings of IAU Symposium 245
"Formation and Evolution of Galaxy Bulges", Eds M. Bureau, E. Athanassoula,
and B. Barbu
Supermassive black holes from OASIS and SAURON integral-field kinematics
Supermassive black holes are a key element in our understanding of how
galaxies form. Most of the progress in this very active field of research is
based on just ~30 determinations of black hole mass, accumulated over the past
decade. We illustrate how integral-field spectroscopy, and in particular our
OASIS modeling effort, can help improve the current situation.Comment: 4 pages, 2 figures, LaTeX. To appear in the proceedings of IAU
Symposium 245 "Formation and Evolution of Galaxy Bulges", M. Bureau, E.
Athanassoula, and B. Barbuy, ed
Testing Mass Determinations of Supermassive Black Holes via Stellar Kinematics
We investigate the accuracy of mass determinations M_BH of supermassive black
holes in galaxies using dynamical models of the stellar kinematics. We compare
10 of our M_BH measurements, using integral-field OASIS kinematics, to
published values. For a sample of 25 galaxies we confront our new M_BH derived
using two modeling methods on the same OASIS data.Comment: 4 pages, 4 figures, LaTeX. To appear in "Hunting for the Dark: The
Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P.
Debattista and C.C. Popescu, AIP Conf. Ser., in pres
The SAURON project - XXI : The spatially resolved UV-line strength relations of early-type galaxies
The unexpected rising flux of early-type galaxies at decreasing ultraviolet (UV) wavelengths is a long-standing mystery. One important observational constraint is the correlation between UVoptical colours and Mg2 line strengths found by Burstein et al. The simplest interpretation of this phenomenon is that the UV strength is related to the Mg line strength. Under this assumption, we expect galaxies with larger Mg gradients to have larger UV colour gradients. By combining UV imaging from GALEX, optical imaging from MDM and SAURON integral-field spectroscopy, we investigate the spatially resolved relationships between UV colours and stellar population properties of 34 early-type galaxies from the SAURON survey sample. We find that galaxies with old stellar populations show tight correlations between the far-UV (FUV) colours (FUV -V and FUV - NUV) and the Mg b index, H beta index and metallicity [Z/H]. The equivalent correlations for the Fe5015 index, a-enhancement [a/Fe] and age are present but weaker. We have also derived logarithmic internal radial colour, measured line strength and derived stellar population gradients for each galaxy and again found a strong dependence of the FUV -V and FUV - NUV colour gradients on both the Mg b line strength and the metallicity gradients for galaxies with old stellar populations. In particular, global gradients of Mg b and [Z/H] with respect to the UV colour [e.g. ?(Mg b)/(FUV - NUV) and ?[Z/H]/?(FUV - NUV)] across galaxies are consistent with their local gradients within galaxies, suggesting that the global correlations also hold locally. From a simple model based on multiband colour fits of UV upturn and UV-weak galaxies, we have identified a plausible range of parameters that reproduces the observed radial colour profiles. In these models, the centres of elliptical galaxies, where the UV flux is strong, are enhanced in metals by roughly 60 per cent compared to UV-weak regions.Peer reviewe
N-methyl-d-aspartate receptor independent changes in expression of polysialic acid-neural cell adhesion molecule despite blockade of homosynaptic long-term potentiation and heterosynaptic long-term depression in the awake freely behaving rat dentate gyrus
Investigations examining the role of polysialic acid (PSA) on the neural cell adhesion molecule (NCAM) in synaptic plasticity have yielded inconsistent data. Here, we addressed this issue by determining whether homosynaptic long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) induce changes in the distribution of PSA-NCAM in the dentate gyrus (DG) of rats in vivo. In addition, we also examined whether the observed modifications were initiated via the activation of N-methyl-d-aspartate (NMDA) receptors. Immunocytochemical analysis showed an increase in PSA-NCAM positive cells both at 2 and 24 h following high-frequency stimulation of either medial or lateral perforant paths, leading to homosynaptic LTP and heterosynaptic LTD, respectively, in the medial molecular layer of the DG. Analysis of sub-cellular distribution of PSA-NCAM by electron microscopy showed decreased PSA dendritic labelling in LTD rats and a sub-cellular relocation towards the spines in LTP rats. Importantly, these modifications were found to be independent of the activation of NMDA receptors. Our findings suggest that strong activation of the granule cells up-regulates PSA-NCAM synthesis which then incorporates into activated synapses, representing NMDA-independent plastic processes that act synergistically on LTP/LTD mechanisms without participating in their expression
The Frequency of Barred Spiral Galaxies in the Near-IR
We have determined the fraction of barred galaxies in the H-band for a
statistically well-defined sample of 186 spirals drawn from the Ohio State
University Bright Spiral Galaxy survey. We find 56% of our sample to be
strongly barred at H, while another 16% is weakly barred. Only 27% of our
sample is unbarred in the near-infrared. The RC3 and the Carnegie Atlas of
Galaxies both classify only about 30% of our sample as strongly barred. Thus
strong bars are nearly twice as prevalent in the near-infrared as in the
optical. The frequency of genuine optically hidden bars is significant, but
lower than many claims in the literature: 40% of the galaxies in our sample
that are classified as unbarred in the RC3 show evidence for a bar in the
H-band, while for the Carnegie Atlas this fraction is 66%. Our data reveal no
significant trend in bar fraction as a function of morphology in either the
optical or H-band. Optical surveys of high redshift galaxies may be strongly
biased against finding bars, as bars are increasingly difficult to detect at
bluer rest wavelengths.Comment: LaTeX with AASTeX style file, 23 pages with 6 figures. Accepted for
publication in The Astronomical Journal (Feb. 2000
On the origin of M81 group extended dust emission
Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over an order of a few arcmin scales, the far-infrared (Herschel 250 mu m) emission correlates spatially very well with a particular narrow-velocity (2-3 km s(-1)) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light-back scattered off dust in our galaxy. Ultraviolet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arcmin scales and that at smaller scales there can be quite large dust-temperature variation
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