3,137 research outputs found
The M_BH-M_star relation of obscured AGNs at high redshift
We report the detection of broad Halpha emission in three X-ray selected
obscured AGNs at z=1-2. By exploiting the Halpha width and the intrinsic X-ray
luminosity, we estimate their black hole masses, which are in the range
0.1-3x10^9 Msun. By means of multi-band photometric data, we measure the
stellar mass of their host galaxy and, therefore, infer their M_BH/M_star
ratio. These are the first obscured AGNs at high-z, selected based on their
black hole accretion (i.e. on the basis of their X-ray luminosity), that can be
located on the M_BH-M_star relation at high-z. All of these obscured high-z
AGNs are fully consistent with the local M_BH-M_star relation. This result
conflicts with those for other samples of AGNs in the same redshift range,
whose M_BH/M_star ratio departs significantly from the value observed in local
galaxies. We suggest that the obscured AGNs in our sample are in an advanced
evolutionary stage, have already settled onto the local M_BH-M_star relation,
and whose nuclear activity has been temporarily revived by recent galaxy
interactions.Comment: 4 pages, 2 figures, accepted for publication in A&A Letters, slightly
revised discussion on SMG
Reduced EGF receptor signalling aggravates signs of post-traumatic osteoarthritis in the calcified tissues of the knee
The star formation rate cookbook at 1 < z < 3: Extinction-corrected relations for UV & [OII]{\lambda}3727 luminosities
We use a spectroscopic sample of 286 star-forming galaxies (SFGs) at 1<z<3
from the GMASS survey to study different star formation rate (SFR) estimators.
Infrared (IR) data are used to derive empirical calibrations to correct
ultraviolet (UV) and [OII]{\lambda}3727 luminosities for dust extinction and
dust-corrected estimates of SFR. In the selection procedure we fully exploit
the available spectroscopic information. On the basis of three continuum
indices, we are able to identify and exclude from the sample galaxies in which
old stellar populations might bring a non-negligible contribution to IR
luminosity (LIR) and continuum reddening. Using Spitzer-MIPS and Herschel-PACS
data we derive LIR for two-thirds of our sample. The LIR/LUV ratio is used as a
probe of effective attenuation (AIRX) to search for correlations with continuum
and spectroscopic features. The relation between AIRX and UV continuum slope
({\beta}) was tested for our sample and found to be broadly consistent with the
literature results at the same redshift, though with a larger dispersion with
respect to UV-selected samples. We find a correlation between the rest-frame
equivalent width (EW) of the [OII]{\lambda}3727 line and {\beta}, which is the
main result of this work. We therefore propose the [OII]{\lambda}3727 line EW
as a dust attenuation probe and calibrate it through AIRX, though the
assumption of a reddening curve is still needed to derive the actual
attenuation towards the [OII]{\lambda}3727 line. We tested the issue of
differential attenuation towards stellar continuum and nebular emission: our
results are in line with the traditional prescription of extra attenuation
towards nebular lines. A set of relations is provided that allows the recovery
of the total unattenuated SFR from UV and [OII]{\lambda}3727 luminosities.
(Abridged)Comment: Accepted for publication in A&A; 20 pages, 19 figures, 5 table
Grasp planning with a soft reconfigurable gripper exploiting embedded and environmental constraints
Grasping in unstructured environments requires highly adaptable and versatile hands together with strategies to exploit their features to get robust grasps. This paper presents a method to grasp objects using a novel reconfigurable soft gripper with embodied constraints, the Soft ScoopGripper (SSG). The considered grasp strategy, called scoop grasp, exploits the SSG features to perform robust grasps. The embodied constraint, i.e., a scoop, is used to slide between the object and a flat surface (e.g., a table or a wall) in contact with it. The fingers are first configured according to object geometry and then used to establish reliable contact with it. Given the object to be grasped, the proposed grasp planner chooses the best configuration of the fingers and the scoop based on the object point cloud and then suitably aligns the gripper to it
Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third Edition - Comments and Statistics
The Catalogue, available at the Centre de Donn\'ees Stellaires de Strasbourg,
consists of 13573 records concerning the results obtained from different
methods for 7778 stars, reported in the literature. The following data are
listed for each star: identifications, apparent magnitude, spectral type,
apparent diameter in arcsec, absolute radius in solar units, method of
determination, reference, remarks. Comments and statistics obtained from CADARS
are given.Comment: A&A, in pres
Analysis of the DNA methylation pattern of the promoter region of calcitonin gene-related peptide 1 gene in patients with episodic migraine: An exploratory case-control study
Recent studies suggested that epigenetic mechanisms, including DNA methylation, may be involved in migraine pathogenesis. The calcitonin gene-related peptide (CGRP), encoded by calcitonin gene-related peptide 1 (CALCA) gene, plays a key role in the disease. The aim of the study was to evaluate DNA methylation of CALCA gene in patients with episodic migraine. 22 patients with episodic migraine (F/M 15/7, mean age 39.7 ± 13.4 years) and 20 controls (F/M 12/8, mean age 40.5 ± 14.8 years) were recruited. Genomic DNA was extracted from peripheral blood. Cytosine-to-thymine conversion was obtained with sodium bisulfite. The methylation pattern of two CpG islands in the promoter region of CALCA gene was analyzed. No difference of methylation of the 30 CpG sites at the distal region of CALCA promoter was observed between migraineurs and controls. Interestingly, in patients with episodic migraine the methylation level was lower in 2 CpG sites at the proximal promoter region (CpG â1461, p = 0.037, and â1415, p = 0.035, respectively). Furthermore, DNA methylation level at different CpG sites correlates with several clinical characteristics of the disease, as age at onset, presence of nausea/vomiting, depression and anxiety (p < 0.05). In conclusion, we found that DNA methylation profile in two CpG sites at the proximal promoter region of CALCA is lower in migraineurs when compared to controls. Intriguingly, the â1415 hypomethylated unit is located at the CREB binding site, a nuclear transcription factor. In addition, we found a correlation between the level of CALCA methylation and several clinical features of migraine. Further studies with larger sample size are needed to confirm these results
A scintillatorâbased approach to monitor secondary neutron production during proton therapy
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135048/1/mp3813.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135048/2/mp3813_am.pd
Unveiling obscured accretion in the Chandra Deep Field South
A large population of heavily obscured, Compton Thick AGNs is predicted by
models of galaxy formation, models of Cosmic X-ray Background and by the
``relic'' super-massive black-hole mass function measured from local bulges.
However, so far only a handful of Compton thick AGNs have been possibly
detected using even the deepest Chandra and XMM surveys. Compton-thick AGNs can
be recovered thanks to the reprocessing of the AGN UV emission in the infrared
by selecting sources with AGN luminosity's in the mid-infrared and faint
near-infrared and optical emission. To this purpose, we make use of deep HST,
VLT, Spitzer and Chandra data on the Chandra Deep Field South to constrain the
number of Compton thick AGN in this field. We show that sources with high
24m to optical flux ratios and red colors form a distinct source
population, and that their infrared luminosity is dominated by AGN emission.
Analysis of the X-ray properties of these extreme sources shows that most of
them (80) are indeed likely to be highly obscured, Compton thick AGNs.
The number of infrared selected, Compton thick AGNs with 5.8m luminosity
higher than erg s turns out to be similar to that of X-ray
selected, unobscured and moderately obscured AGNs with 2-10 keV luminosity
higher than erg s in the redshift bin 1.2-2.6. This ``factor
of 2'' source population is exactly what it is needed to solve the
discrepancies between model predictions and X-ray AGN selection.Comment: Revised version, to be published by The Astrophysical Journa
Vitamin D status in cord blood and newborns: ethnic differences.
BACKGROUND: A deficiency in vitamin D (25OHD) is common throughout the world in both adults and children, being related to skin pigmentation, sun exposure, dietary intake and obesity. Limited data are available for the neonatal age. The aim of the study is to understand the differences in 25OHD levels with respect to skin colour and ethnicity in newborns.
METHODS: We randomly enrolled 62 neonates, born at term and appropriate for gestational age. Thirty two were born from Italian mothers with fair skin (FS) and 30 from non-Caucasian mothers (North African, African, Asian and Latin American): 10 with light olive/light brown (LOB) and 20 with medium brown/black skin (MBB). Vitamin D was measured in the cord blood at birth and in neonatal serum during metabolic screening.
RESULTS: 25OHD levels were (mean\u2009\ub1\u2009SD) 21.4\u2009\ub1\u200911 ng/ml in cord blood and 14.9\u2009\ub1\u20097 ng/ml in serum after birth. 25OHD values were higher in cord blood (p\u2009<\u20090.01) and neonatal serum (p\u2009<\u20090.001) in subjects supplemented with Vitamin D. Newborn FS showed higher vitamin D levels in cord blood when compared to LOB and MBB (p\u2009<\u20090.01), and higher levels in neonatal serum when compared to LOB (p\u2009<\u20090.01). In cord blood, 25OHD levels were higher in Italian newborns than in North African (p\u2009<\u20090.004) and African (p\u2009<\u20090.01). In neonatal serum, 25OHD levels were higher in Italian infants only when compared with North African infants (p\u2009<\u20090.03).
CONCLUSIONS: The present study shows a high prevalence of vitamin D insufficiency and deficiency in newborns with significant differences observed to be due to ethnicity, skin colour and maternal supplementation during the pregnancy
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