207 research outputs found
Deep Gaussian Denoiser Epistemic Uncertainty and Decoupled Dual-Attention Fusion
Following the performance breakthrough of denoising networks, improvements
have come chiefly through novel architecture designs and increased depth. While
novel denoising networks were designed for real images coming from different
distributions, or for specific applications, comparatively small improvement
was achieved on Gaussian denoising. The denoising solutions suffer from
epistemic uncertainty that can limit further advancements. This uncertainty is
traditionally mitigated through different ensemble approaches. However, such
ensembles are prohibitively costly with deep networks, which are already large
in size.
Our work focuses on pushing the performance limits of state-of-the-art
methods on Gaussian denoising. We propose a model-agnostic approach for
reducing epistemic uncertainty while using only a single pretrained network. We
achieve this by tapping into the epistemic uncertainty through augmented and
frequency-manipulated images to obtain denoised images with varying error. We
propose an ensemble method with two decoupled attention paths, over the pixel
domain and over that of our different manipulations, to learn the final fusion.
Our results significantly improve over the state-of-the-art baselines and
across varying noise levels.Comment: Code and models are publicly available on https://github.com/IVRL/DE
Stellar Population Properties and Evolution Analysis of NGC 628 with the Panchromatic Photometry
Panchromatic spectral energy distribution (SED) from the ultraviolet (UV),
optical to infrared (IR) photometry of NGC 628, combined with the evolutionary
stellar population synthesis, is used to derive the spatially resolved age,
metallicity and reddening maps. These parameter distributions show that the
bulge of this galaxy is a disk-like pseudobulge, which has the S{\'e}rsic index
close to the exponential law, rich gas, and a young circumnuclear ring
structure. We also discover the disk has two distinct regions with different
radial age and metallicity gradients. The inner region is older and has a much
steeper age gradient than the outer region of the disk. Both these two regions
and the central young structure can be seen in the radial profile of the
optical color. Based on the age and reddening distributions, we consider that
the pseudobulge and disk are likely to have grown via the secular evolution,
which is the redistribution of mass and energy through the angular momentum
transport caused by the non-axisymmetric potential of the spirals. However,
possible gas accretion events could affect the outer region of the disk, due to
abundant H{\sc i} gas accumulating in the outer disk.Comment: 9 figures, accepted for publication in A
The Imperial IRAS-FSC Redshift Catalogue: luminosity functions, evolution and galaxy bias
We present the luminosity function and selection function of 60 micron
galaxies selected from the Imperial IRAS-FSC Redshift Catalogue (IIFSCz). Three
methods, including the 1/Vmax} and the parametric and non-parametric maximum
likelihood estimator, are used and results agree well with each other. A
density evolution proportional to (1+z)^3.4 or a luminosity evolution exp(1.7
t_L / \tau)$ where t_L is the look-back time is detected in the full sample in
the redshift range [0.02, 0.1], consistent with previous analyses. Of the four
infrared subpopulations, cirrus-type galaxies and M82-type starbursts show
similar evolutionary trends, galaxies with significant AGN contributions show
stronger positive evolution and Arp 220-type starbursts exhibit strong negative
evolution. The dominant subpopulation changes from cirrus-type galaxies to
M82-type starbursts at log (L_60 / L_Sun) ~ 10.3.
In the second half of the paper, we derive the projected two-point spatial
correlation function for galaxies of different infrared template type. The mean
relative bias between cirrus-type galaxies and M82-type starbursts, which
correspond to quiescent galaxies with optically thin interstellar dust and
actively star-forming galaxies respectively, is calculated to be around 1.25.
The relation between current star formation rate (SFR) in star-forming galaxies
and environment is investigated by looking at the the dependence of clustering
on infrared luminosity. We found that M82-type actively star-forming galaxies
show stronger clustering as infrared luminosity / SFR increases. The
correlation between clustering strength and SFR in the local Universe seems to
echo the basic trend seen in star-forming galaxies in the Great Observatories
Origins Deep Survey (GOODS) fields at z ~ 1.Comment: 15 pages, 11 figures, accepted for publication in MNRA
Pre-cooling for endurance exercise performance in the heat: a systematic review.
PMCID: PMC3568721The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/166.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Endurance exercise capacity diminishes under hot environmental conditions. Time to exhaustion can be increased by lowering body temperature prior to exercise (pre-cooling). This systematic literature review synthesizes the current findings of the effects of pre-cooling on endurance exercise performance, providing guidance for clinical practice and further research
Exceptional AGN-driven turbulence inhibits star formation in the 3C 326N radio galaxy
We detect bright [CII]158ÎŒm line emission from the radio galaxy 3C 326N at z=0.09, which shows weak star formation (SFRâ~yrâ1) despite having strong H2 line emission and 2Ă109Mâ of molecular gas. The [CII] line is twice as strong as the 0-0S(1) 17ÎŒm H2 line, and both lines are much in excess what is expected from UV heating. We combine infrared Spitzer and Herschel data with gas and dust modeling to infer the gas physical conditions. The [CII] line traces 30 to 50% of the molecular gas mass, which is warm (70â3. The [CII] line is broad with a blue-shifted wing, and likely to be shaped by a combination of rotation, outflowing gas, and turbulence. It matches the near-infrared H2 and the Na D optical absorption lines. If the wing is interpreted as an outflow, the mass loss rate would be larger than 20Mâ/yr, and the depletion timescale shorter than the orbital timescale (108yr). These outflow rates may be over-estimated because the stochastic injection of turbulence on galactic scales can contribute to the skewness of the line profile and mimic outflowing gas. We argue that the dissipation of turbulence is the main heating process of this gas. Cosmic rays can also contribute to the heating but they require an average gas density larger than the observational constraints. We show that strong turbulent support maintains a high gas vertical scale height (0.3-4kpc) in the disk and can inhibit the formation of gravitationally-bound structures at all scales, offering a natural explanation for the weakness of star formation in 3C 326N. To conclude, the bright [CII] line indicates that strong AGN jet-driven turbulence may play a key role in enhancing the amount of molecular gas (positive feedback) but yet can prevent star formation on galactic scales (negative feedback)
The structure and characteristic scales of the H I gas in galactic disks
The spatial distribution of the HâŻI gas in galactic disks holds important clues about the physical processes that shape the structure and dynamics of the interstellar medium (ISM). The structure of the ISM could be affected by a variety of perturbations internal and external to the galaxy, and the unique signature of each of these perturbations could be visible in the structure of interstellar gas. In this work, we quantify the structure of the HâŻI gas in a sample of 33 nearby galaxies taken from the HI Nearby Galaxy Survey (THINGS) using the delta-variance (Î-variance) spectrum. The THINGS galaxies display a large diversity in their spectra, but there are a number of recurrent features. In many galaxies, we observe a bump in the spectrum on scales of a few to several hundred parsec. We find the characteristic scales associated with the bump to be correlated with the galactic star formation rate (SFR) for values of the SFR âł0.5 Mâ yrâ1 and also with the median size of the HâŻI shells detected in these galaxies. We interpret this characteristic scale as being associated with the effects of feedback from supernova explosions. On larger scales, we observe in most galaxies two self-similar, scale-free regimes. The first regime, on intermediate scales (âČ0.5R25), is shallow, and the power law that describes this regime has an exponent in the range [0.1â1] with a mean value of 0.55 that is compatible with the density field that is generated by supersonic turbulence in the cold phase of the HâŻI gas. The second power law is steeper, with a range of exponents between 0.5 and 2.3 and a mean value of â1.5. These values are associated with subsonic to transonic turbulence, which is characteristic of the warm phase of the HâŻI gas. The spatial scale at which the transition between the two self-similar regimes occurs is found to be â0.5R25, which is very similar to the size of the molecular disk in the THINGS galaxies. Overall, our results suggest that on scales âČ0.5R25, the structure of the ISM is affected by the effects of supernova explosions. On larger scales (âł0.5R25), stellar feedback has no significant impact, and the structure of the ISM is determined by large-scale processes that govern the dynamics of the gas in the warm neutral medium, such as the flaring of the HâŻI disk at large galactocentric radii and the effects of ram pressure stripping
The physical scale of the far-infrared emission in the most luminous submillimetre galaxies II: evidence for merger-driven star formation
We present high-resolution 345 GHz interferometric observations of two
extreme luminous (L_{IR}>10^{13} L_sun), submillimetre-selected galaxies (SMGs)
in the COSMOS field with the Submillimeter Array (SMA). Both targets were
previously detected as unresolved point-sources by the SMA in its compact
configuration, also at 345 GHz. These new data, which provide a factor of ~3
improvement in resolution, allow us to measure the physical scale of the
far-infrared in the submillimetre directly. The visibility functions of both
targets show significant evidence for structure on 0.5-1 arcsec scales, which
at z=1.5 translates into a physical scale of 5-8 kpc. Our results are
consistent with the angular and physical scales of two comparably luminous
objects with high-resolution SMA followup, as well as radio continuum and CO
sizes. These relatively compact sizes (<5-10 kpc) argue strongly for
merger-driven starbursts, rather than extended gas-rich disks, as the preferred
channel for forming SMGs. For the most luminous objects, the derived sizes may
also have important physical consequences; under a series of simplifying
assumptions, we find that these two objects in particular are forming stars
close to or at the Eddington limit for a starburst.Comment: 9 pages, 3 Figures, submitted to MNRA
Scientific Synergy between LSST and Euclid
Euclid and the Large Synoptic Survey Telescope (LSST) are poised to dramatically change the astronomy landscape early in the next decade. The combination of high-cadence, deep, wide-field optical photometry from LSST with high-resolution, wide-field optical photometry, and near-infrared photometry and spectroscopy from Euclid will be powerful for addressing a wide range of astrophysical questions. We explore Euclid/LSST synergy, ignoring the political issues associated with data access to focus on the scientific, technical, and financial benefits of coordination. We focus primarily on dark energy cosmology, but also discuss galaxy evolution, transient objects, solar system science, and galaxy cluster studies. We concentrate on synergies that require coordination in cadence or survey overlap, or would benefit from pixel-level co-processing that is beyond the scope of what is currently planned, rather than scientific programs that could be accomplished only at the catalog level without coordination in data processing or survey strategies. We provide two quantitative examples of scientific synergies: the decrease in photo-z errors (benefiting many science cases) when high-resolution Euclid data are used for LSST photo-z determination, and the resulting increase in weak-lensing signal-to-noise ratio from smaller photo-z errors. We briefly discuss other areas of coordination, including high-performance computing resources and calibration data. Finally, we address concerns about the loss of independence and potential cross-checks between the two missions and the potential consequences of not collaborating
Up-regulation of cell cycle arrest protein BTG2 correlates with increased overall survival in breast cancer, as detected by immunohistochemistry using tissue microarray
<p>Abstract</p> <p>Background</p> <p>Previous studies have shown that the <it>ADIPOR1</it>, <it>ADORA1</it>, <it>BTG2 </it>and <it>CD46 </it>genes differ significantly between long-term survivors of breast cancer and deceased patients, both in levels of gene expression and DNA copy numbers. The aim of this study was to characterize the expression of the corresponding proteins in breast carcinoma and to determine their correlation with clinical outcome.</p> <p>Methods</p> <p>Protein expression was evaluated using immunohistochemistry in an independent breast cancer cohort of 144 samples represented on tissue microarrays. Fisher's exact test was used to analyze the differences in protein expression between dead and alive patients. We used Cox-regression multivariate analysis to assess whether the new markers predict the survival status of the patients better than the currently used markers.</p> <p>Results</p> <p>BTG2 expression was demonstrated in a significantly lower proportion of samples from dead patients compared to alive patients, both in overall expression (<it>P </it>= 0.026) and cell membrane specific expression (<it>P </it>= 0.013), whereas neither ADIPOR1, ADORA1 nor CD46 showed differential expression in the two survival groups. Furthermore, a multivariate analysis showed that a model containing BTG2 expression in combination with HER2 and Ki67 expression along with patient age performed better than a model containing the currently used prognostic markers (tumour size, nodal status, HER2 expression, hormone receptor status, histological grade, and patient age). Interestingly, BTG2 has previously been described as a tumour suppressor gene involved in cell cycle arrest and p53 signalling.</p> <p>Conclusions</p> <p>We conclude that high-level BTG2 protein expression correlates with prolonged survival in patients with breast carcinoma.</p
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