1,523 research outputs found

    The Millennium Galaxy Catalogue: morphological classification and bimodality in the colour-concentration plane

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    Using 10 095 galaxies (B < 20 mag) from the Millennium Galaxy Catalogue, we derive B-band luminosity distributions and selected bivariate brightness distributions for the galaxy population. All subdivisions extract highly correlated sub-sets of the galaxy population which consistently point towards two overlapping distributions. A clear bimodality in the observed distribution is seen in both the rest-(u-r) colour and log(n) distributions. The rest-(u-r) colour bimodality becomes more pronounced when using the core colour as opposed to global colour. The two populations are extremely well separated in the colour-log(n) plane. Using our sample of 3 314 (B < 19 mag) eyeball classified galaxies, we show that the bulge-dominated, early-type galaxies populate one peak and the bulge-less, late-type galaxies occupy the second. The early- and mid-type spirals sprawl across and between the peaks. This constitutes extremely strong evidence that the fundamental way to divide the luminous galaxy population is into bulges and discs and that the galaxy bimodality reflects the two component nature of galaxies and not two distinct galaxy classes. We argue that these two-components require two independent formation mechanisms/processes and advocate early bulge formation through initial collapse and ongoing disc formation through splashback, infall and merging/accretion. We calculate the B-band luminosity-densities and stellar-mass densities within each subdivision and estimate that the z ~ 0 stellar mass content in spheroids, bulges and discs is 35 +/- 2 per cent, 18 +/- 7 and 47 +/- 7 per cent respectively. [Abridged]Comment: Accepted for publication in MNRAS, 23 pages, 17 figures. Comments welcome. MGC website is at: http://www.eso.org/~jliske/mgc

    Abciximab reduces mortality in diabetics following percutaneous coronary intervention

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    AbstractOBJECTIVESWe sought to determine whether abciximab therapy at the time of percutaneous coronary intervention (PCI) would favorably affect one-year mortality in patients with diabetes.BACKGROUNDDiabetics are known to have increased late mortality following PCI.METHODSData from three placebo-controlled trials of PCI, EPIC, EPILOG, and EPISTENT, were pooled. The one-year mortality rate for patients with a clinical diagnosis of diabetes mellitus was compared with the rate for nondiabetic patients treated with either abciximab or placebo.RESULTSIn the 1,462 diabetic patients, abciximab decreased the mortality from 4.5% to 2.5%, p = 0.031, and in the 5,072 nondiabetic patients, from 2.6% to 1.9%, p = 0.099. In patients with the clinical syndrome of insulin resistance—defined as diabetes, hypertension, and obesity—mortality was reduced by abciximab treatment from 5.1% to 2.3%, p = 0.044. The beneficial reduction in mortality with abciximab use in diabetics classified as insulin-requiring was from 8.1% to 4.2%, p = 0.073. Mortality in diabetics who underwent multivessel intervention was reduced from 7.7% to 0.9% with use of abciximab, p = 0.018. In a Cox proportional hazards survival model, the risk ratio for mortality with abciximab use compared with placebo was 0.642 (95% confidence interval 0.458–0.900, p = 0.010).CONCLUSIONSAbciximab decreases the mortality of diabetic patients to the level of placebo-treated nondiabetic patients. This beneficial effect is noteworthy in those diabetic patients who are also hypertensive and obese and in diabetics undergoing multivessel intervention. Besides its potential role in reducing repeat intervention for stented diabetic patients, abciximab therapy should be strongly considered in diabetic patients undergoing PCI to improve their survival

    The duration of pretreatment with ticlopidine prior to stenting is associated with the risk of procedure-related non–Q-wave myocardial infarctions

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    AbstractObjectives. This study sought to determine whether the duration of pretreatment with the adenosine diphosphate receptor antagonist ticlopidine prior to intracoronary stenting is associated with the incidence of procedure-related non–Q-wave myocardial infarctions (MIs).Background. Dual antiplatelet therapy with ticlopidine and aspirin is routinely used with stenting, although ticlopidine is commonly not begun until the day of the procedure. Periprocedural MIs are at least partially platelet-dependent events. As the maximal platelet inhibitory effects of this drug take 2 to 3 days to be realized, we hypothesized that longer treatment prior to stenting would be associated with lower rates of procedure-related MIs.Methods. We reviewed outcomes in 175 consecutive patients treated with ticlopidine prior to stenting at the Cleveland Clinic Foundation. Those patients with an elevation in creatine kinase above our laboratory normal (>210 IU/L) with ≄4% MB fraction on routine evaluation were defined as having a non–Q-wave MI.Results. There were 28 patients (16%) who had a non–Q-wave MI. Longer duration of ticlopidine pretreatment was strongly associated with a lower incidence of procedure-related non–Q-wave MIs (duration of pretreatment <1 day, 29% had MI; 1 to 2 days, 14%; ≄3 days, 5%; chi-square for trend = 9.6; p = 0.002). Ticlopidine pretreatment of ≄3 days was associated with a significant reduction in the risk of non–Q-wave MI (unadjusted odds ratio 0.18, 95% confidence interval = 0.04 to 0.78, p = 0.01) compared with pretreatment of <3 days.Conclusions. Among patients undergoing intracoronary stenting, beginning ticlopidine therapy several days prior to the procedure is associated with a reduced risk of procedural non–Q-wave MIs

    GEMS: Galaxy Evolution from Morphologies and SEDs

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    GEMS, Galaxy Evolution from Morphologies and SEDs, is a large-area (800 arcmin2) two-color (F606W and F850LP) imaging survey with the Advanced Camera for Surveys on HST. Centered on the Chandra Deep Field South, it covers an area of ~28'x28', or about 120 Hubble Deep Field areas, to a depth of m_AB(F606W)=28.3 (5sigma and m_AB(F850LP)=27.1 (5sigma) for compact sources. In its central ~1/4, GEMS incorporates ACS imaging from the GOODS project. Focusing on the redshift range 0.2<=z<=1.1, GEMS provides morphologies and structural parameters for nearly 10,000 galaxies where redshift estimates, luminosities and SEDs exist from COMBO-17. At the same time, GEMS contains detectable host galaxy images for several hundred faint AGN. This paper provides an overview of the science goals, the experiment design, the data reduction and the science analysis plan for GEMS.Comment: 24 pages, TeX with 6 eps Figures; to appear in ApJ Supplement. Low resolution figures only. Full resolution at http://zwicky.as.arizona.edu/~rix/Misc/GEMS.ps.g
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