12,154 research outputs found
Characterizing Uncertainty in Air Pollution Damage Estimates
This study uses Monte Carlo methods to characterize the uncertainty associated with per-ton damage estimates for 100 power plants in the contiguous United States (U.S.) This analysis focuses on damage estimates produced by an Integrated Assessment Model (IAM) for emissions of two local air pollutants: sulfur dioxide (SO2) and .ne particulate matter (PM2:5). For each power plant, the Monte Carlo procedure yields an empirical distribution for the damage per ton of SO2 and PM2:5:For a power plant in New York, one ton of SO2 produces 1,000 and 17,790 worth of damages with a 90% percentile interval of 47,930. Results for the sample of 100 fossil-fuel .red power plants shows a strong spatial pattern in the marginal damage distributions. The degree of variability increases by plant location from east to west. This result highlights the importance of capturing uncertainty in air quality modeling in the empirical marginal damage distributions. Further, by isolating uncertainty at each module in the IAM we .nd that uncertainty associated with the dose-response parameter, which captures the in.uence of exposure to PM2:5 on adult mortality rates, the mortality valuation parameter, and the air quality model exert the greatest in.uence on cumulative uncertainty. The paper also demonstrates how the marginal damage distributions may be used to guide regulators in the design of more efficient market-based air pollution policy in the U.S.Monte Carlo, Air Pollution, Market-based Pollution Policy
A volume-based hydrodynamic approach to sound wave propagation in a monatomic gas
We investigate sound wave propagation in a monatomic gas using a volume-based
hydrodynamic model. In Physica A vol 387(24) (2008) pp6079-6094, a microscopic
volume-based kinetic approach was proposed by analyzing molecular spatial
distributions; this led to a set of hydrodynamic equations incorporating a
mass-density diffusion component. Here we find that these new mass-density
diffusive flux and volume terms mean that our hydrodynamic model, uniquely,
reproduces sound wave phase speed and damping measurements with excellent
agreement over the full range of Knudsen number. In the high Knudsen number
(high frequency) regime, our volume-based model predictions agree with the
plane standing waves observed in the experiments, which existing kinetic and
continuum models have great difficulty in capturing. In that regime, our
results indicate that the "sound waves" presumed in the experiments may be
better thought of as "mass-density waves", rather than the pressure waves of
the continuum regime.Comment: Revised to aid clarification (no changes to presented model); typos
corrected, figures added, paper title change
Dielectronic Recombination of Fe XV forming Fe XIV: Laboratory Measurements and Theoretical Calculations
We have measured resonance strengths and energies for dielectronic
recombination (DR) of Mg-like Fe XV forming Al-like Fe XIV via N=3 -> N' = 3
core excitations in the electron-ion collision energy range 0-45 eV. All
measurements were carried out using the heavy-ion Test Storage Ring at the Max
Planck Institute for Nuclear Physics in Heidelberg, Germany. We have also
carried out new multiconfiguration Breit-Pauli (MCBP) calculations using the
AUTOSTRUCTURE code. For electron-ion collision energies < 25 eV we find poor
agreement between our experimental and theoretical resonance energies and
strengths. From 25 to 42 eV we find good agreement between the two for
resonance energies. But in this energy range the theoretical resonance
strengths are ~ 31% larger than the experimental results. This is larger than
our estimated total experimental uncertainty in this energy range of +/- 26%
(at a 90% confidence level). Above 42 eV the difference in the shape between
the calculated and measured 3s3p(^1P_1)nl DR series limit we attribute partly
to the nl dependence of the detection probabilities of high Rydberg states in
the experiment. We have used our measurements, supplemented by our
AUTOSTRUCTURE calculations, to produce a Maxwellian-averaged 3 -> 3 DR rate
coefficient for Fe XV forming Fe XIV. The resulting rate coefficient is
estimated to be accurate to better than +/- 29% (at a 90% confidence level) for
k_BT_e > 1 eV. At temperatures of k_BT_e ~ 2.5-15 eV, where Fe XV is predicted
to form in photoionized plasmas, significant discrepancies are found between
our experimentally-derived rate coefficient and previously published
theoretical results. Our new MCBP plasma rate coefficient is 19-28% smaller
than our experimental results over this temperature range
Renormalization of heavy-light currents in moving NRQCD
Heavy-light decays such as , and can be used to constrain the parameters of the Standard
Model and in indirect searches for new physics. While the precision of
experimental results has improved over the last years this has still to be
matched by equally precise theoretical predictions. The calculation of
heavy-light form factors is currently carried out in lattice QCD. Due to its
small Compton wavelength we discretize the heavy quark in an effective
non-relativistic theory. By formulating the theory in a moving frame of
reference discretization errors in the final state are reduced at large recoil.
Over the last years the formalism has been improved and tested extensively.
Systematic uncertainties are reduced by renormalizing the m(oving)NRQCD action
and heavy-light decay operators. The theory differs from QCD only for large
loop momenta at the order of the lattice cutoff and the calculation can be
carried out in perturbation theory as an expansion in the strong coupling
constant. In this paper we calculate the one loop corrections to the
heavy-light vector and tensor operator. Due to the complexity of the action the
generation of lattice Feynman rules is automated and loop integrals are solved
by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and
ultraviolet divergences in the loop integrals both in the continuum and on the
lattice. The light quarks are discretized in the ASQTad and highly improved
staggered quark (HISQ) action; the formalism is easily extended to other quark
actions.Comment: 24 pages, 11 figures. Published in Phys. Rev. D. Corrected a typo in
eqn. (51
Doping dependence of the coupling of electrons to bosonic modes in the single-layer high-temperature Bi2Sr2CuO6 superconductor
A recent highlight in the study of high-Tc superconductors is the observation
of band renormalization / self-energy effects on the quasiparticles. This is
seen in the form of kinks in the quasiparticle dispersions as measured by
photoemission and interpreted as signatures of collective bosonic modes
coupling to the electrons. Here we compare for the first time the self-energies
in an optimally doped and strongly overdoped, non-superconducting single-layer
Bi-cuprate (Bi2Sr2CuO6). Besides the appearance of a strong overall weakening,
we also find that weight of the self-energy in the overdoped system shifts to
higher energies. We present evidence that this is related to a change in the
coupling to c-axis phonons due to the rapid change of the c-axis screening in
this doping range.Comment: 4 pages, 3 figure
Antioxidant, antibacterial and cell toxicity effects of polyphenols Fromahmeur bouamer grape seed extracts
In this work and for the first time, significant concentrations of total polyphenols and flavonoids from Vitis vinifera L. grape seed extracts were obtained (256.15 ± 17.40 mg GAE/gdm and 14.08 ± 0.64 mg CE/gdm, respectively).The LC/MS analysis revealed richness in procyanidins. For antioxidant, antimicrobial and antifungal effects, the grape seed extract (GSE) responded positively. At 100 μg/mL, GSE induced a moderate toxicity of the order of 3.88% on 3T6 cells at the first 24 hours of treatment, whereas, its prolonged effect to 48 hours reduced this toxicity to less than 0.5%. As for the anti-proliferative effect on tumoral cell lines, a cell death of 18.39% to 23.79% and 10.30% to 20.37% was registered respectively for HeLa and BCPAP cells during 24 and 48 hours of treatment. Consequently, it is possible to consider using GSE at lower concentrations as an anti-proliferative agent without losing sight of its benefic effect on healthy cells.Keywords: grape seed extract, 3T6 cell, antioxidant, antibacterial, anti-proliferation
Quasi-elastic neutron scattering in the high-field phase of a Haldane antiferromagnet
Inelastic neutron scattering experiments on the Haldane-gap quantum
antiferromagnet NDMAP are performed in magnetic fields below and above the
critical field Hc at which the gap closes. Quasi-elastic neutron scattering is
found for H>Hc indicating topological excitations in the high field phase.Comment: Added to discussion section. v2: Updated figure
Empirical Evaluation of Deep Learning Approaches for Landmark Detection in Fish Bioimages
In this paper we perform an empirical evaluation of variants of deep learning methods to automatically localize anatomical landmarks in bioimages of fishes acquired using different imaging modalities (microscopy and radiography). We compare two methodologies namely heatmap based regression and multivariate direct regression, and evaluate them in combination with several Convolutional Neural Network (CNN) architectures. Heatmap based regression approaches employ Gaussian or Exponential heatmap generation functions combined with CNNs to output the heatmaps corresponding to landmark locations whereas direct regression approaches output directly the (x, y) coordinates corresponding to landmark locations. In our experiments, we use two microscopy datasets of Zebrafish and Medaka fish and one radiography dataset of gilthead Seabream. On our three datasets, the heatmap approach with Exponential function and U-Net architecture performs better.
Datasets and open-source code for training and prediction are made available to ease future landmark detection research and bioimaging applications
Electron detachment from negative ions in bichromatic laser field
Negative ion detachment in two-colour laser field is considered within the
recent modification of Keldysh model which makes it quantitatively reliable.
The general approach is illustrated by calculation of angular differential
detachment rates, partial rates for particular ATD (Above Threshold Detachment)
channels and total detachment rates for H ion in bichromatic field with 1:2
frequency ratio. Both perturbative and strong field regimes are examined. Polar
asymmetry and phase effects are quantitatively characterized with some new
features revealed. Phase effects are found to result in a huge anisotropy
factor in the electron angular distribution in the perturbative
regime.Comment: 13 pages, 8 figures in separate files which are not incorporated in
the latex file of the pape
Experimental demonstration of counterfactual quantum key distribution
Counterfactual quantum key distribution provides natural advantage against
the eavesdropping on the actual signal particles. It can prevent the
photon-number-splitting attack when a weak coherent light source is used for
the practical implementation. We realized the counterfactual quantum key
distribution in an unbalanced Mach-Zehnder interferometer of 12.5-km-long
quantum channel with a high-fringe visibility of 96:4%. As a result, we
obtained secure keys against the noise-induced attack (eg. the vacuum attack)
and passive photon-number-splitting attack.Comment: 5 pages, 3 figure
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