1,412 research outputs found
Implications of the unusual structure in the pp correlation from Pb+Pb collisions at 158 AGeV
The recent NA49 measurement of two-proton correlation function shows an
interesting and unexpected structure at large relative momentum. Applying
source imaging techniques to the measurement, we find an unusually steep
drop-off in the two-proton source function. We show that the steep drop-off is
due to the structure in the correlation and the drop-off cannot be explained
using conventional correlation analysis. We suggest possible physics reasons
for the unusual source function.Comment: 6 pages, 3 eps figures, uses RevTex.sty. To appear in Physics Letters
B. Updated 10/26/99 with cleaner figures and added discussions of analysis
done in nucl-ex/9905001 and of imagin
Optimal Tableaux Method for Constructive Satisfiability Testing and Model Synthesis in the Alternating-time Temporal Logic ATL+
We develop a sound, complete and practically implementable tableaux-based
decision method for constructive satisfiability testing and model synthesis in
the fragment ATL+ of the full Alternating time temporal logic ATL*. The method
extends in an essential way a previously developed tableaux-based decision
method for ATL and works in 2EXPTIME, which is the optimal worst case
complexity of the satisfiability problem for ATL+ . We also discuss how
suitable parametrizations and syntactic restrictions on the class of input ATL+
formulae can reduce the complexity of the satisfiability problem.Comment: 45 page
Mechanism of activation of H2O2 by peroxidases: kinetic studies on a model system
AbstractKinetic studies on the peroxidase activity of microperoxidase-8 at pH 5.5â8.5 show that the rate is increased by raising the pH or by the presence of guanidinium ion. Comparison with published data on the peroxidases provides evidence that the enzyme activates H2O2 through the cooperative binding of H+ + HOâ2 and suggests a role for the invariant distal Arg
Measuring velocity ratios with correlation functions
We show how to determine the ratio of the transverse velocity of a source to
the velocity of emitted particles, using split-bin correlation functions. The
technique is to measure and , subtract the contributions from
the single-particle distribution, and take the ratio as the bin size goes to
zero. We demonstrate the technique for two cases: each source decays into two
particles, and each source emits a large number of particles.Comment: 9 pages, LaTeX, 2 PostScript figure
Imaging of Sources in Heavy-Ion Reactions
Imaging of sources from data within the intensity interferometry is
discussed. In the two-pion case, the relative pion source function may be
determined through the Fourier transformation of the correlation function. In
the proton-proton case, the discretized source function may be fitted to the
correlation data.Comment: 12 pages, 3 postscript figures, accepted Physics Letters
Interactive Medical Image Segmentation using Deep Learning with Image-specific Fine-tuning
Convolutional neural networks (CNNs) have achieved state-of-the-art
performance for automatic medical image segmentation. However, they have not
demonstrated sufficiently accurate and robust results for clinical use. In
addition, they are limited by the lack of image-specific adaptation and the
lack of generalizability to previously unseen object classes. To address these
problems, we propose a novel deep learning-based framework for interactive
segmentation by incorporating CNNs into a bounding box and scribble-based
segmentation pipeline. We propose image-specific fine-tuning to make a CNN
model adaptive to a specific test image, which can be either unsupervised
(without additional user interactions) or supervised (with additional
scribbles). We also propose a weighted loss function considering network and
interaction-based uncertainty for the fine-tuning. We applied this framework to
two applications: 2D segmentation of multiple organs from fetal MR slices,
where only two types of these organs were annotated for training; and 3D
segmentation of brain tumor core (excluding edema) and whole brain tumor
(including edema) from different MR sequences, where only tumor cores in one MR
sequence were annotated for training. Experimental results show that 1) our
model is more robust to segment previously unseen objects than state-of-the-art
CNNs; 2) image-specific fine-tuning with the proposed weighted loss function
significantly improves segmentation accuracy; and 3) our method leads to
accurate results with fewer user interactions and less user time than
traditional interactive segmentation methods.Comment: 11 pages, 11 figure
Is the Faroe Bank Channel overflow hydraulically controlled?
Author Posting. © American Meteorological Society, 2006. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 36 (2006): 2340-2349, doi:10.1175/JPO2969.1.The overflow of dense water from the Nordic Seas through the Faroe Bank Channel (FBC) has attributes suggesting hydraulic controlâprimarily an asymmetry across the sill reminiscent of flow over a dam. However, this aspect has never been confirmed by any quantitative measure, nor is the position of the control section known. This paper presents a comparison of several different techniques for assessing the hydraulic criticality of oceanic overflows applied to data from a set of velocity and hydrographic sections across the FBC. These include 1) the cross-stream variation in the local Froude number, including a modified form that accounts for stratification and vertical shear, 2) rotating hydraulic solutions using a constant potential vorticity layer in a channel of parabolic cross section, and 3) direct computation of shallow water wave speeds from the observed overflow structure. Though differences exist, the three methods give similar answers, suggesting that the FBC is indeed controlled, with a critical section located 20â90 km downstream of the sill crest. Evidence of an upstream control with respect to a potential vorticity wave is also presented. The implications of these results for hydraulic predictions of overflow transport and variability are discussed.The Faroe Bank Channel experiment
was supported by NSF Grant OCE-9906736. JBG
gratefully acknowledges the support of the NOAA/
UCAR Climate and Global Change Postdoctoral Program
and NSF Grant OCE-9985840. Author Price was
supported in part by the U.S. Office of Naval Research
through Grant N00014-04-1-0109
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