951 research outputs found
Foreground removal from WMAP 7yr polarization maps using an MLP neural network
One of the fundamental problems in extracting the cosmic microwave background
signal (CMB) from millimeter/submillimeter observations is the pollution by
emission from the Milky Way: synchrotron, free-free, and thermal dust emission.
To extract the fundamental cosmological parameters from CMB signal, it is
mandatory to minimize this pollution since it will create systematic errors in
the CMB power spectra. In previous investigations, it has been demonstrated
that the neural network method provide high quality CMB maps from temperature
data. Here the analysis is extended to polarization maps. As a concrete
example, the WMAP 7-year polarization data, the most reliable determination of
the polarization properties of the CMB, has been analysed. The analysis has
adopted the frequency maps, noise models, window functions and the foreground
models as provided by the WMAP Team, and no auxiliary data is included. Within
this framework it is demonstrated that the network can extract the CMB
polarization signal with no sign of pollution by the polarized foregrounds. The
errors in the derived polarization power spectra are improved compared to the
errors derived by the WMAP Team.Comment: Accepted for publication in Astrophysics & Space Scienc
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Elevated fetal steroidogenic activity in autism
Autism affects males more than females, giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor. Utilizing the Danish Historic Birth Cohort and Danish Psychiatric Central Register, we identified all amniotic fluid samples of males born between 1993 and 1999 who later received ICD-10 (International Classification of Diseases, 10th Revision) diagnoses of autism, Asperger syndrome or PDD-NOS (pervasive developmental disorder not otherwise specified) (n=128) compared with matched typically developing controls. Concentration levels of Î4 sex steroids (progesterone, 17Îą-hydroxy-progesterone, androstenedione and testosterone) and cortisol were measured with liquid chromatography tandem mass spectrometry. All hormones were positively associated with each other and principal component analysis confirmed that one generalized latent steroidogenic factor was driving much of the variation in the data. The autism group showed elevations across all hormones on this latent generalized steroidogenic factor (Cohen's d=0.37, P=0.0009) and this elevation was uniform across ICD-10 diagnostic label. These results provide the first direct evidence of elevated fetal steroidogenic activity in autism. Such elevations may be important as epigenetic fetal programming mechanisms and may interact with other important pathophysiological factors in autism
Recovering the properties of high redshift galaxies with different JWST broad-band filters
Imaging with the James Webb Space Telescope (JWST) will allow for observing
the bulk of distant galaxies at the epoch of reionisation. The recovery of
their properties, such as age, color excess E(B-V), specific star formation
rate (sSFR) and stellar mass, will mostly rely on spectral energy distribution
fitting, based on the data provided by JWST's two imager cameras, namely the
Near Infrared Camera (NIRCam) and the Mid Infrared Imager (MIRI). In this work
we analyze the effect of choosing different combinations of NIRCam and MIRI
broad-band filters, from 0.6 {\mu}m to 7.7 {\mu}m, on the recovery of these
galaxy properties. We performed our tests on a sample of 1542 simulated
galaxies, with known input properties, at z=7-10. We found that, with only 8
NIRCam broad-bands, we can recover the galaxy age within 0.1 Gyr and the color
excess within 0.06 mag for 70% of the galaxies. Besides, the stellar masses and
sSFR are recovered within 0.2 and 0.3 dex, respectively, at z=7-9. Instead, at
z=10, no NIRCam band traces purely the {\lambda}> 4000 {\AA} regime and the
percentage of outliers in stellar mass (sSFR) increases by > 20% (> 90%), in
comparison to z=9. The MIRI F560W and F770W bands are crucial to improve the
stellar mass and the sSFR estimation at z=10. When nebular emission lines are
present, deriving correct galaxy properties is challenging, at any redshift and
with any band combination. In particular, the stellar mass is systematically
overestimated in up to 0.3 dex on average with NIRCam data alone and including
MIRI observations improves only marginally the estimation.Comment: 21 pages, 11 figures, 4 tables. Accepted for publication at the ApJ
Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor.
Nine human small-cell lung cancer cell lines were treated with transforming growth factor beta 1 (TGF-beta 1). Seven of the cell lines expressed receptors for transforming growth factor beta (TGF-beta-r) in different combinations between the three human subtypes I, II and III, and two were receptor negative. Growth suppression was induced by TGF-beta 1 exclusively in the five cell lines expressing the type II receptor. For the first time growth suppression by TGF-beta 1 of a cell line expressing the type II receptor without coexpression of the type I receptor is reported. No effect on growth was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required for mediation of TGF-beta 1-induced growth suppression
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