1,649 research outputs found
Noise-Net: Determining physical properties of HII regions reflecting observational uncertainties
Stellar feedback, the energetic interaction between young stars and their
birthplace, plays an important role in the star formation history of the
universe and the evolution of the interstellar medium (ISM). Correctly
interpreting the observations of star-forming regions is essential to
understand stellar feedback, but it is a non-trivial task due to the complexity
of the feedback processes and degeneracy in observations. In our recent paper,
we introduced a conditional invertible neural network (cINN) that predicts
seven physical properties of star-forming regions from the luminosity of 12
optical emission lines as a novel method to analyze degenerate observations. We
demonstrated that our network, trained on synthetic star-forming region models
produced by the WARPFIELD-Emission predictor (WARPFIELD-EMP), could predict
physical properties accurately and precisely. In this paper, we present a new
updated version of the cINN that takes into account the observational
uncertainties during network training. Our new network named Noise-Net reflects
the influence of the uncertainty on the parameter prediction by using both
emission-line luminosity and corresponding uncertainties as the necessary input
information of the network. We examine the performance of the Noise-Net as a
function of the uncertainty and compare it with the previous version of the
cINN, which does not learn uncertainties during the training. We confirm that
the Noise-Net outperforms the previous network for the typical observational
uncertainty range and maintains high accuracy even when subject to large
uncertainties.Comment: 22 pages, 14 figures, Accepted for publication by MNRAS on 04.
Januar
Phonon Density of States of LaFeAsO1-xFx
We have studied the phonon density of states (PDOS) in LaFeAsO1-xFx with
inelastic neutron scattering methods. The PDOS of the parent compound(x=0) is
very similar to the PDOS of samples optimally doped with fluorine to achieve
the maximum Tc (x~0.1). Good agreement is found between the experimental PDOS
and first-principle calculations with the exception of a small difference in Fe
mode frequencies. The PDOS reported here is not consistent with conventional
electron-phonon mediated superconductivity
Actin Filaments in Mature Guard Cells Are Radially Distributed and Involved in Stomatal Movement
PECTINASE-MODIFIED RED GINSENG (GS-E3D) INHIBIT NF-ΚB TRANSLOCATION AND NITRIC OXIDE PRODUCTION IN LIPOPOLYSACCHARIDE-STIMULATED RAW 264.7 CELLS
Objective: Red ginseng has been used as traditional medicines and functional foods in the world, because of its health benefits. The aim of this study was to elucidate the anti-inflammatory effect and mechanism of pectinase-modified red ginseng (GS-E3D) with a cellular model of lipopolysaccharide (LPS)-stimulated RAW264.7 cells.Methods: To study the anti-inflammatory effect of GS-E3D, the key inflammation mediators such as nitric oxide (NO),prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), Cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukin (IL)-6 production as well as on nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) activation, were measured by using the enzyme linked immunosorbent assay (ELISA)and Western blotting.Results: GS-E3D potently inhibited TNF-α and IL-6 and also diminished NO over-production, which was accompanied by the down-regulation of iNOS expression. GS-E3D effectively suppressed LPS-induced NF-κB activation through inhibiting the hyper-phosphorylation and degradation of IκB-α and phosphorylation of p38, ERK1/2 and JNK in MAPK signaling pathway.Conclusion: GS-E3D has a potential to be as an anti-inflammatory agent for functional food or cosmetic materials targeting on the NF-κB p65 and MAPKs signaling pathways.Â
The rise of policy coherence for development: a multi-causal approach
In recent years policy coherence for development (PCD) has become a key principle in international development debates, and it is likely to become even more relevant in the discussions on the post-2015 sustainable development goals. This article addresses the rise of PCD on the Western donors’ aid agenda. While the concept already appeared in the work of Organisation for Economic Co-operation and Development (OECD) in the early 1990s, it took until 2007 before PCD became one of the Organisation’s key priorities. We adopt a complexity-sensitive perspective, involving a process-tracing analysis and a multi-causal explanatory framework. We argue that the rise of PCD is not as contingent as it looks. While actors such as the EU, the DAC and OECD Secretariat were the ‘active causes’ of the rise of PCD, it is equally important to look at the underlying ‘constitutive causes’ which enabled policy coherence to thrive well
Collider and Dark Matter Searches in Models with Mixed Modulus-Anomaly Mediated SUSY Breaking
We investigate the phenomenology of supersymmetric models where moduli fields
and the Weyl anomaly make comparable contributions to SUSY breaking effects in
the observable sector of fields. This mixed modulus-anomaly mediated
supersymmetry breaking (MM-AMSB) scenario is inspired by models of string
compactification with fluxes, which have been shown to yield a de Sitter vacuum
(as in the recent construction by Kachru {\it et al}). The phenomenology
depends on the so-called modular weights which, in turn, depend on the location
of various fields in the extra dimensions. We find that the model with zero
modular weights gives mass spectra characterized by very light top squarks
and/or tau sleptons, or where M_1\sim -M_2 so that the bino and wino are
approximately degenerate. The top squark mass can be in the range required by
successful electroweak baryogenesis. The measured relic density of cold dark
matter can be obtained via top squark co-annihilation at low \tan\beta, tau
slepton co-annihilation at large \tan\beta or via bino-wino coannihilation.
Then, we typically find low rates for direct and indirect detection of
neutralino dark matter. However, essentially all the WMAP-allowed parameter
space can be probed by experiments at the CERN LHC, while significant portions
may also be explored at an e^+e^- collider with \sqrt{s}=0.5--1 TeV. We also
investigate a case with non-zero modular weights. In this case,
co-annihilation, A-funnel annihilation and bulk annihilation of neutralinos are
all allowed. Results for future colliders are qualitatively similar, but
prospects for indirect dark matter searches via gamma rays and anti-particles
are somewhat better.Comment: 38 pages including 22 EPS figures; latest version posted to conform
with published versio
Probing scrambling using statistical correlations between randomized measurements
We propose and analyze a protocol to study quantum information scrambling
using statistical correlations between measurements, which are performed after
evolving a quantum system from randomized initial states. We prove that the
resulting correlations precisely capture the so-called out-of-time-ordered
correlators and can be used to probe chaos in strongly-interacting, many-body
systems. Our protocol requires neither reversing time evolution nor auxiliary
degrees of freedom, and can be realized in state-of-the-art quantum simulation
experiments.Comment: This version v2 (8 pages, 7 figures) includes important new results
compared to our original submission. (1) We present a protocol and
corresponding mathematical proof to access OTOCs with local operations, and
which can be realized in quantum simulation experiments with available
technology. (2) We illustrate the realization of the protocols with different
examples for Hubbard and spin model
Optimizing linear discriminant error correcting output codes using particle swarm optimization
Error Correcting Output Codes reveal an efficient strategy in dealing with multi-class classification problems. According to this technique, a multi-class problem is decomposed into several binary ones. On these created sub-problems we apply binary classifiers and then, by combining the acquired solutions, we are able to solve the initial multi-class problem. In this paper we consider the optimization of the Linear Discriminant Error Correcting Output Codes framework using Particle Swarm Optimization. In particular, we apply the Particle Swarm Optimization algorithm in order to optimally select the free parameters that control the split of the initial problem's classes into sub-classes. Moreover, by using the Support Vector Machine as classifier we can additionally apply the Particle Swarm Optimization algorithm to tune its free parameters. Our experimental results show that by applying Particle Swarm Optimization on the Sub-class Linear Discriminant Error Correcting Output Codes framework we get a significant improvement in the classification performance. © 2011 Springer-Verlag
System-Size Independence of Directed Flow Measured at the BNL Relativistic Heavy-Ion Collider
We measure directed flow (ν_1) for charged particles in Au+Au and Cu+Cu collisions at √S_(NN)=200 and 62.4 GeV, as a function of pseudorapidity (η), transverse momentum (p_t), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to ν_1 in different collision systems, and investigate possible explanations for the observed sign change in ν_1(p_t)
Observation of charge-dependent azimuthal correlations and possible local strong parity violation in heavy ion collisions
Parity-odd domains, corresponding to non-trivial topological solutions of the
QCD vacuum, might be created during relativistic heavy-ion collisions. These
domains are predicted to lead to charge separation of quarks along the orbital
momentum of the system created in non-central collisions. To study this effect,
we investigate a three particle mixed harmonics azimuthal correlator which is a
\P-even observable, but directly sensitive to the charge separation effect. We
report measurements of this observable using the STAR detector in Au+Au and
Cu+Cu collisions at =200 and 62~GeV. The results are presented
as a function of collision centrality, particle separation in rapidity, and
particle transverse momentum. A signal consistent with several of the
theoretical expectations is detected in all four data sets. We compare our
results to the predictions of existing event generators, and discuss in detail
possible contributions from other effects that are not related to parity
violation.Comment: 17 pages, 14 figures, as accepted for publication in Physical Review
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