361 research outputs found
Search for the Radiative Capture d+d->^4He+\gamma Reaction from the dd\mu Muonic Molecule State
A search for the muon catalyzed fusion reaction dd --> ^4He +\gamma in the
dd\mu muonic molecule was performed using the experimental \mu CF installation
TRITON and NaI(Tl) detectors for \gamma-quanta. The high pressure target filled
with deuterium at temperatures from 85 K to 800 K was exposed to the negative
muon beam of the JINR phasotron to detect \gamma-quanta with energy 23.8 MeV.
The first experimental estimation for the yield of the radiative deuteron
capture from the dd\mu state J=1 was obtained at the level n_{\gamma}\leq
2\times 10^{-5} per one fusion.Comment: 9 pages, 3 Postscript figures, submitted to Phys. At. Nuc
Phase distortions of attosecond pulses produced by resonance-enhanced high harmonic generation
Resonant enhancement of high harmonic generation can be obtained in plasmas
containing ions with strong radiative transitions resonant with harmonic
orders. The mechanism for this enhancement is still debated. We perform the
first temporal characterization of the attosecond emission from a tin plasma
under near-resonant conditions for two different resonance detunings. We show
that the resonance considerably changes the relative phase of neighbouring
harmonics. For very small detunings, their phase locking may even be lost,
evidencing strong phase distortions in the emission process and a modified
attosecond structure. These features are well reproduced by our simulations,
allowing their interpretation in terms of the phase of the recombination dipole
moment
Neutron Resonance Capture Analysis (NRCA), elemental compositions of bronze age objects
Prehistory of Nortwestern Europ
Finite Temperature Aging Holography
We construct the gravity background which describes the dual field theory
with aging invariance. We choose the decay modes of the bulk scalar field in
the internal spectator direction to obtain the dissipative behavior of the
boundary correlation functions of the dual scalar fields. In particular, the
two-time correlation function at zero temperature has the characteristic
features of the aging system: power law decay, broken time translation and
dynamical scaling. We also construct the black hole backgrounds with asymptotic
aging invariance. We extensively study characteristic behavior of the finite
temperature two-point correlation function via analytic and numerical methods.Comment: 38 pages and 5 figures, expanded discussions on correlator, one
mistake is fixed, modified discussion on shear viscosity, to appear in JHE
Bevacizumab for metachronous metastatic colorectal cancer: a reflection of community based practice
Deep Learning assessment of galaxy morphology in S-PLUS Data Release 1
The morphological diversity of galaxies is a relevant probe of galaxy evolution and cosmological structure formation, but the classification of galaxies in large sky surveys is becoming a significant challenge. We use data from the Stripe-82 area observed by the Southern Photometric Local Universe Survey (S-PLUS) in 12 optical bands, and present a catalogue of the morphologies of galaxies brighter than r = 17 mag determined both using a novel multiband morphometric fitting technique and Convolutional Neural Networks (CNNs) for computer vision. Using the CNNs, we find that, compared to our baseline results with three bands, the performance increases when using 5 broad and 3 narrow bands, but is poorer when using the full 12 band S-PLUS image set. However, the best result is still achieved with just three optical bands when using pre-trained network weights from an ImageNet data set. These results demonstrate the importance of using prior knowledge about neural network weights based on training in unrelated, extensive data sets, when available. Our catalogue contains 3274 galaxies in Stripe-82 that are not present in Galaxy Zoo 1 (GZ1), and we also provide our classifications for 4686 galaxies that were considered ambiguous in GZ1. Finally, we present a prospect of a novel way to take advantage of 12 band information for morphological classification using morphometric features, and we release a model that has been pre-trained on several bands that could be adapted for classifications using data from other surveys. The morphological catalogues are publicly available.Fil: Bom, C. R.. Centro Brasileiro de Pesquisa Fisicas; BrasilFil: Cortesi, A.. Valongo Observatory; BrasilFil: Lucatelli, G.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Dias, L. O.. Centro Brasileiro de Pesquisa Fisicas; BrasilFil: Schubert, P.. Centro Brasileiro de Pesquisa Fisicas; BrasilFil: Oliveira Schwarz, G. B.. Universidade Presbiteriana Mackenzie; BrasilFil: Cardoso, N. M.. Universidade de Sao Paulo; BrasilFil: Lima, E. V. R.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Mendes de Oliveira, C.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Sodre, L.. Universidade do Sao Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas; BrasilFil: Smith Castelli, Analia Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Ferrari, F.. Universidade Federal Do Rio Grande.; BrasilFil: Damke, G.. Universidad de La Serena; ChileFil: Overzier, R.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; BrasilFil: Kanaan, A.. Universidade Federal Da Santa Catarina. Cent.de Cs Físicas E Matemáticas. Departamento de Física; BrasilFil: Ribeiro, T.. Universidade Federal do Rio Grande do Sul; BrasilFil: Schoenell, W.. Noao; Estados Unido
S-PLUS DR1 galaxy clusters and groups catalogue using PzWav
We present a catalogue of 4499 groups and clusters of galaxies from the first
data release of the multi-filter (5 broad, 7 narrow) Southern Photometric Local
Universe Survey (S-PLUS). These groups and clusters are distributed over 273
deg in the Stripe 82 region. They are found using the PzWav algorithm,
which identifies peaks in galaxy density maps that have been smoothed by a
cluster scale difference-of-Gaussians kernel to isolate clusters and groups.
Using a simulation-based mock catalogue, we estimate the purity and
completeness of cluster detections: at S/N>3.3 we define a catalogue that is
80% pure and complete in the redshift range 0.1<z<0.4, for clusters with
M. We also assessed the accuracy of the catalogue
in terms of central positions and redshifts, finding scatter of
kpc and , respectively. Moreover, less than 1% of
the sample suffers from fragmentation or overmerging. The S-PLUS cluster
catalogue recovers ~80% of all known X-ray and Sunyaev-Zel'dovich selected
clusters in this field. This fraction is very close to the estimated
completeness, thus validating the mock data analysis and paving an efficient
way to find new groups and clusters of galaxies using data from the ongoing
S-PLUS project. When complete, S-PLUS will have surveyed 9300 deg of the
sky, representing the widest uninterrupted areas with narrow-through-broad
multi-band photometry for cluster follow-up studies.Comment: 17 pages, 15 figures, paper accepted for publication by MNRA
Mitogen activated protein kinases SakA(HOG1) and MpkC collaborate for Aspergillus fumigatus virulence
Here, we investigated which stress responses were influenced by the MpkC and SakA mitogen-activated protein kinases of the high-osmolarity glycerol (HOG) pathway in the fungal pathogen Aspergillus fumigatus. The DsakA and the double Delta mpkC Delta sakA mutants were more sensitive to osmotic and oxidative stresses, and to cell wall damaging agents. Both MpkC:: GFP and SakA:: GFP translocated to the nucleus upon osmotic stress and cell wall damage, with SakA:: GFP showing a quicker response. The phosphorylation state of MpkA was determined post exposure to high concentrations of congo red and Sorbitol. In the wild-type strain, MpkA phosphorylation levels progressively increased in both treatments. In contrast, the Delta sakA mutant had reduced MpkA phosphorylation, and surprisingly, the double Delta mpkC Delta sakA had no detectable MpkA phosphorylation. A. fumigatus DsakA and DmpkC were virulent in mouse survival experiments, but they had a 40% reduction in fungal burden. In contrast, the Delta mpkC Delta sakA double mutant showed highly attenuated virulence, with approximately 50% mice surviving and a 75% reduction in fungal burden. We propose that both cell wall integrity (CWI) and HOG pathways collaborate, and that MpkC could act by modulating SakA activity upon exposure to several types of stresses and during CW biosynthesis
Schr\"odinger Holography with and without Hyperscaling Violation
We study the properties of the Schr\"odinger-type non-relativistic holography
for general dynamical exponent z with and without hyperscaling violation
exponent \theta. The scalar correlation function has a more general form due to
general z as well as the presence of \theta, whose effects also modify the
scaling dimension of the scalar operator. We propose a prescription for minimal
surfaces of this "codimension 2 holography," and demonstrate the (d-1)
dimensional area law for the entanglement entropy from (d+3) dimensional
Schr\"odinger backgrounds. Surprisingly, the area law is violated for d+1 < z <
d+2, even without hyperscaling violation, which interpolates between the
logarithmic violation and extensive volume dependence of entanglement entropy.
Similar violations are also found in the presence of the hyperscaling
violation. Their dual field theories are expected to have novel phases for the
parameter range, including Fermi surface. We also analyze string theory
embeddings using non-relativistic branes.Comment: 62 pages and 6 figures, v2: several typos in section 5 corrected,
references added, v3: typos corrected, references added, published versio
The strong gravitational lens finding challenge
Large-scale imaging surveys will increase the number of galaxy-scale strong lensing candidates by maybe three orders of magnitudes beyond the number known today. Finding these rare objects will require picking them out of at least tens of millions of images, and deriving scientific results from them will require quantifying the efficiency and bias of any search method. To achieve these objectives automated methods must be developed. Because gravitational lenses are rare objects, reducing false positives will be particularly important. We present a description and results of an open gravitational lens finding challenge. Participants were asked to classify 100 000 candidate objects as to whether they were gravitational lenses or not with the goal of developing better automated methods for finding lenses in large data sets. A variety of methods were used including visual inspection, arc and ring finders, support vector machines (SVM) and convolutional neural networks (CNN). We find that many of the methods will be easily fast enough to analyse the anticipated data flow. In test data, several methods are able to identify upwards of half the lenses after applying some thresholds on the lens characteristics such as lensed image brightness, size or contrast with the lens galaxy without making a single false-positive identification. This is significantly better than direct inspection by humans was able to do. Having multi-band, ground based data is found to be better for this purpose than single-band space based data with lower noise and higher resolution, suggesting that multi-colour data is crucial. Multi-band space based data will be superior to ground based data. The most difficult challenge for a lens finder is differentiating between rare, irregular and ring-like face-on galaxies and true gravitational lenses. The degree to which the efficiency and biases of lens finders can be quantified largely depends on the realism of the simulated data on which the finders are trained
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