31 research outputs found

    Planck intermediate results. XXI. Comparison of polarized thermal emission from Galactic dust at 353 GHz with interstellar polarization in the visible

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    The Planck survey provides unprecedented full-sky coverage of the submillimetre polarized emission from Galactic dust. In addition to the information on the direction of the Galactic magnetic field, this also brings new constraints on the properties of dust. The dust grains that emit the radiation seen by Planck in the submillimetre also extinguish and polarize starlight in the visible. Comparison of the polarization of the emission and of the interstellar polarization on selected lines of sight probed by stars provides unique new diagnostics of the emission and light scattering properties of dust, and therefore of the important dust model parameters, composition, size, and shape. Using ancillary catalogues of interstellar polarization and extinction of starlight, we obtain the degree of polarization, p(V), and the optical depth in the V band to the star, tau(V). Toward these stars we measure the submillimetre polarized intensity, P-S, and total intensity, I-S,I- in the Planck 353 GHz channel. We compare the column density measure in the visible, E(B - V), with that inferred from the Planck product map of the submillimetre dust optical depth and compare the polarization direction (position angle) in the visible with that in the submillimetre. For those lines of sight through the di ff use interstellar medium with comparable values of the estimated column density and polarization directions close to orthogonal, we correlate properties in the submillimetre and visible to find two ratios, R-S/V = (P-S/I-S) = (p(V)/tau(V)) and R-P/p = P-S/p(V), the latter focusing directly on the polarization properties of the aligned grain population alone. We find R-S/V = 4.2, with statistical and systematic uncertainties 0.2 and 0.3, respectively, and R-P/p = 5.4 MJy sr(-1), with uncertainties 0.2 and 0.3 MJy sr(-1), respectively. Our estimate of R-S/V is compatible with predictions based on a range of polarizing dust models that have been developed for the di ff use interstellar medium. This estimate provides new empirical validation of many of the common underlying assumptions of the models, but is not yet very discriminating among them. However, our estimate of R-P/p is not compatible with predictions, which are too low by a factor of about 2.5. This more discriminating diagnostic, R-P/p, indicates that changes to the optical properties in the models of the aligned grain population are required. These new diagnostics, together with the spectral dependence in the submillimetre from Planck, will be important for constraining and understanding the full complexity of the grain models, and for interpreting the Planck thermal dust polarization and refinement of the separation of this contamination of the cosmic microwave background.Peer reviewe

    Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust

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    This paper presents an overview of the polarized sky as seen by Planck HFI at 353GHz, which is the most sensitive Planck channel for dust polarization. We construct and analyse maps of dust polarization fraction and polarization angle at 1 degrees resolution, taking into account noise bias and possible systematic effects. The sensitivity of the Planck HFI polarization measurements allows for the first time a mapping of Galactic dust polarized emission on large scales, including low column density regions. We find that the maximum observed dust polarization fraction is high (p(max) = 19.8%), in particular in some regions of moderate hydrogen column density (N-H <2 x 10(21) cm(-2)). The polarization fraction displays a large scatter at NH below a few 10(21) cm(-2). There is a general decrease in the dust polarization fraction with increasing column density above N-H similar or equal to 1 x 10(21) cm(-2) and in particular a sharp drop above N-H similar or equal to 1.5 x 10(22) cm(-2). We characterize the spatial structure of the polarization angle using the angle dispersion function. We find that the polarization angle is ordered over extended areas of several square degrees, separated by filamentary structures of high angle dispersion function. These appear as interfaces where the sky projection of the magnetic field changes abruptly without variations in the column density. The polarization fraction is found to be anti-correlated with the dispersion of polarization angles. These results suggest that, at the resolution of 1 degrees, depolarization is due mainly to fluctuations in the magnetic field orientation along the line of sight, rather than to the loss of grain alignment in shielded regions. We also compare the polarization of thermal dust emission with that of synchrotron measured with Planck, low-frequency radio data, and Faraday rotation measurements toward extragalactic sources. These components bear resemblance along the Galactic plane and in some regions such as the Fan and North Polar Spur regions. The poor match observed in other regions shows, however, that dust, cosmic-ray electrons, and thermal electrons generally sample different parts of the line of sight.Peer reviewe

    Impact of clinical phenotypes on management and outcomes in European atrial fibrillation patients: a report from the ESC-EHRA EURObservational Research Programme in AF (EORP-AF) General Long-Term Registry

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    Background: Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients\u2019 clinical phenotypes and analyse the differential clinical course. Methods: We performed a hierarchical cluster analysis based on Ward\u2019s Method and Squared Euclidean Distance using 22 clinical binary variables, identifying the optimal number of clusters. We investigated differences in clinical management, use of healthcare resources and outcomes in a cohort of European AF patients from a Europe-wide observational registry. Results: A total of 9363 were available for this analysis. We identified three clusters: Cluster 1 (n = 3634; 38.8%) characterized by older patients and prevalent non-cardiac comorbidities; Cluster 2 (n = 2774; 29.6%) characterized by younger patients with low prevalence of comorbidities; Cluster 3 (n = 2955;31.6%) characterized by patients\u2019 prevalent cardiovascular risk factors/comorbidities. Over a mean follow-up of 22.5 months, Cluster 3 had the highest rate of cardiovascular events, all-cause death, and the composite outcome (combining the previous two) compared to Cluster 1 and Cluster 2 (all P &lt;.001). An adjusted Cox regression showed that compared to Cluster 2, Cluster 3 (hazard ratio (HR) 2.87, 95% confidence interval (CI) 2.27\u20133.62; HR 3.42, 95%CI 2.72\u20134.31; HR 2.79, 95%CI 2.32\u20133.35), and Cluster 1 (HR 1.88, 95%CI 1.48\u20132.38; HR 2.50, 95%CI 1.98\u20133.15; HR 2.09, 95%CI 1.74\u20132.51) reported a higher risk for the three outcomes respectively. Conclusions: In European AF patients, three main clusters were identified, differentiated by differential presence of comorbidities. Both non-cardiac and cardiac comorbidities clusters were found to be associated with an increased risk of major adverse outcomes

    The hypocholesterolemic activity of a?a? (Euterpe oleracea Mart.) is mediated by the enhanced expression of the ATP-binding cassette, subfamily G transporters 5 and 8 and low-density lipoprotein receptor genes in the rat.

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    Previous studies have demonstrated that the ingestion of a?a? pulp can improve serum lipid profile in various animal models; therefore, we hypothesized that a?a? pulp (Euterpe oleracea Mart.) may modulate the expression of the genes involved in cholesterol homeostasis in the liver and increase fecal excretion, thus reducing serum cholesterol. To test this hypothesis, we analyzed the expression of 7?-hydroxylase and ATP-binding cassette, subfamily G transporters (ABCG5 and ABCG8), which are genes involved with the secretion of cholesterol in the rat. We also evaluated the expression of sterol regulatory element?binding protein 2, 3-hydroxy-3-methylglutaryl CoA reductase, low-density lipoprotein receptor (LDL-R), and apolipoprotein B100, which are involved in cholesterol biosynthesis. Female Fischer rats were divided into 4 groups: the C group, which was fed a standard AIN-93 M diet; the CA group, which was fed a standard diet supplemented with 2% a?a? pulp; the H group, which was fed a hypercholesterolemic diet (25% soy oil and 1% cholesterol); and the HA group, which was fed a hypercholesterolemic diet supplemented with 2% a?a? pulp. At the end of the experimental period, the rats were euthanized, and their blood and livers were collected. The HA group exhibited a significant decrease in serum total cholesterol, low-density lipoprotein cholesterol, and atherogenic index and also had increased high-density lipoprotein cholesterol and cholesterol excretion in feces compared with the H group. In addition, the expression of the LDL-R, ABCG5, and ABCG8 genes was significantly increased by the presence of a?a? pulp. These results suggest that a?a? pulp promotes a hypocholesterolemic effect in a rat model of dietary-induced hypercholesterolemia through an increase in the expression of ATP-binding cassette, subfamily G transporters and LDL-R genes
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