451 research outputs found
The contribution of cause-effect link to representing the core of scientific paper—The role of Semantic Link Network
The Semantic Link Network is a general semantic model for modeling the structure and the evolution of complex systems. Various semantic links play different roles in rendering the semantics of complex system. One of the basic semantic links represents cause-effect relation, which plays an important role in representation and understanding. This paper verifies the role of the Semantic Link Network in representing the core of text by investigating the contribution of cause-effect link to representing the core of scientific papers. Research carries out with the following steps: (1) Two propositions on the contribution of cause-effect link in rendering the core of paper are proposed and verified through a statistical survey, which shows that the sentences on cause-effect links cover about 65% of key words within each paper on average. (2) An algorithm based on syntactic patterns is designed for automatically extracting cause-effect link from scientific papers, which recalls about 70% of manually annotated cause-effect links on average, indicating that the result adapts to the scale of data sets. (3) The effects of cause-effect link on four schemes of incorporating cause-effect link into the existing instances of the Semantic Link Network for enhancing the summarization of scientific papers are investigated. The experiments show that the quality of the summaries is significantly improved, which verifies the role of semantic links. The significance of this research lies in two aspects: (1) it verifies that the Semantic Link Network connects the important concepts to render the core of text; and, (2) it provides an evidence for realizing content services such as summarization, recommendation and question answering based on the Semantic Link Network, and it can inspire relevant research on content computing
Improved survival with lymph node sampling in Wilms tumor
We sought to determine the impact of number of lymph nodes examined on survival for Wilms tumor (WT).
Data from the Surveillance, Epidemiology, and End Results and Florida Cancer Data System were queried for patients < 20 years of age with WT.
Of 1805 WT patients, 1340 had lymph node (LN) data available following surgery. The mean age for the cohort was 3.3 ± 2.8 y. Most patients were White (78%), and non-Hispanic (78%). A total of 297 patients (22%) had 0 LN sampled, while 697 (52%) had 1–5 LN, 210 (16%) had 6–10 LN, and 136 (10%) had >10 LN. Overall 5-y survival was 91%. By univariate analysis, 5-y survival was significantly lower for patients with 0 LN sampled (87%
versus 91% 1–5 LN; 93% 6–10 LN; 95% >10 LN,
P = 0.005). Multivariate analysis confirmed a survival advantage for patients having 1–5 LN (HR 0.600,
P = 0.016), 6–10 LN (HR 0.521,
P = 0.048), and >10 LN (HR 0.403,
P = 0.039) compared with patients with 0 LN examined.
Failure to biopsy lymph nodes for WT patients not only increases the risk of local recurrence due to understaging and inadequate adjuvant therapy, but is also an independent prognostic indicator of lower survival
Truncated post-Newtonian neutron star model
As a preliminary step towards simulating binary neutron star coalescing
problem, we test a post-Newtonian approach by constructing a single neutron
star model. We expand the Tolman-Oppenheimer-Volkov equation of hydrostatic
equilibrium by the power of , where is the speed of light, and
truncate at the various order. We solve the system using the polytropic
equation of state with index and 3, and show how this
approximation converges together with mass-radius relations. Next, we solve the
Hamiltonian constraint equation with these density profiles as trial functions,
and examine the differences in the final metric. We conclude the second
`post-Newtonian' approximation is close enough to describe general relativistic
single star. The result of this report will be useful for further binary
studies.
(Note to readers) This paper was accepted for publication in Physical Review
D. [access code dsj637]. However, since I was strongly suggested that the
contents of this paper should be included as a section in our group's future
paper, I gave up the publication.Comment: 5 pages, RevTeX, 3 eps figs, epsf.sty, accepted for publication in
PRD (Brief Report), but will not appea
Prospects for gravitational-wave observations of neutron-star tidal disruption in neutron-star/black-hole binaries
For an inspiraling neutron-star/black-hole binary (NS/BH), we estimate the
gravity-wave frequency f_td at the onset of NS tidal disruption. We model the
NS as a tidally distorted, homogeneous, Newtonian ellipsoid on a circular,
equatorial geodesic around a Kerr BH. We find that f_td depends strongly on the
NS radius R, and estimate that LIGO-II (ca. 2006-2008) might measure R to 15%
precision at 140 Mpc (about 1 event/yr under current estimates). This suggests
that LIGO-II might extract valuable information about the NS equation of state
from tidal-disruption waves.Comment: RevTeX, 4 pages, 2 EPS figures. Revised slightly, corrected typo
Gravitational Radiation from Triple Star Systems
We have studied the main features of the gravitational radiation generated by
an astrophysical system constituted of three compact objects attracting one
another (only via gravitational interaction) in such a manner that stable
orbits do exist. We have limited our analysis to systems that can be treated
with perturbative methods. We show the profile of the gravitational waves
emitted by such systems. These results can be useful within the framework of
the new gravitational astronomy which will be made feasible by means of the new
generation of gravitational detectors such as LISA in a no longer far future.Comment: 10 pages plus 9 postscript figures; revtex; accepted for publication
in Int. J. Mod. Phys.
Binary Neutron-Star Systems: From the Newtonian Regime to the Last Stable Orbit
We report on the first calculations of fully relativistic binary circular
orbits to span a range of separation distances from the innermost stable
circular orbit (ISCO), deeply inside the strong field regime, to a distance
( 200 km) where the system is accurately described by Newtonian dynamics.
We consider a binary system composed of two identical corotating neutron stars,
with 1.43 gravitational mass each in isolation. Using a conformally
flat spatial metric we find solutions to the initial value equations that
correspond to semi-stable circular orbits. At large distance, our numerical
results agree exceedingly well with the Newtonian limit. We also present a self
consistent determination of the ISCO for different stellar masses.Comment: 4 pages, 3 postscript figures. Data points added to fig 2; some
issues clarified; references adde
Gravitational Radiation from Rotational Instabilities in Compact Stellar Cores with Stiff Equations of State
We carry out 3-D numerical simulations of the dynamical instability in
rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and
0.5. The calculations are done with a SPH code using Newtonian gravity, and the
gravitational radiation is calculated in the quadrupole limit. All models
develop the global m=2 bar mode, with mass and angular momentum being shed from
the ends of the bar in two trailing spiral arms. The models then undergo
successive episodes of core recontraction and spiral arm ejection, with the
number of these episodes increasing as n decreases: this results in
longer-lived gravitational wave signals for stiffer models. This instability
may operate in a stellar core that has expended its nuclear fuel and is
prevented from further collapse due to centrifugal forces. The actual values of
the gravitational radiation amplitudes and frequencies depend sensitively on
the radius of the star R_{eq} at which the instability develops.Comment: 39 pages, uses Latex 2.09. To be published in the Dec. 15, 1996 issue
of Physical Review D. 21 figures (bitmapped). Originals available in
compressed Postscript format at ftp://zonker.drexel.edu/papers/bars
Functionalized Copper Nanoparticles with Gold Nanoclusters: Part I. Highly Selective Electrosynthesis of Hydrogen Peroxide
© 2023 The Authors. Published by American Chemical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Copper nanoparticles (CuNPs) and gold nanoclusters (AuNCs) show a high catalytic performance in generating hydrogen peroxide (H2O2), a property that can be exploited to kill disease-causing microbes and to carry carbon-free energy. Some combinations of NPs/NCs can generate synergistic effects to produce stronger antiseptics, such as H2O2 or other reactive oxygen species (ROS). Herein, we demonstrate a novel facile AuNC surface decoration method on the surfaces of CuNPs using galvanic displacement. The Cu–Au bimetallic NPs presented a high selective production of H2O2 via a two-electron (2e–) oxygen reduction reaction (ORR). Their physicochemical analyses were conducted by scanning electron microscopy (SEM), transmitting electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). With the optimized Cu–Au1.5NPs showing their particle sizes averaged in 53.8 nm, their electrochemical analysis indicated that the pristine AuNC structure exhibited the highest 2e– selectivity in ORR, the CuNPs presented the weakest 2e– selectivity, and the optimized Cu–Au1.5NPs exhibited a high 2e– selectivity of 95% for H2O2 production, along with excellent catalytic activity and durability. The optimized Cu–Au1.5NPs demonstrated a novel pathway to balance the cost and catalytic performance through the appropriate combination of metal NPs/NCs.Peer reviewe
Accretion dynamics in neutron star black hole binaries
We perform three-dimensional, Newtonian hydrodynamic simulations with a
nuclear equation of state to investigate the accretion dynamics in neutron star
black hole systems. We find as a general result that non-spinning donor stars
yield larger circularization radii than corotating donors. Therefore, the
matter from a neutron star without spin will more likely settle into an
accretion disk outside the Schwarzschild radius. With the used stiff equation
of state we find it hard to form an accretion disk that is promising to launch
a gamma-ray burst. In all relevant cases the core of the neutron star survives
and keeps orbiting the black hole as a mini neutron star for the rest of the
simulation time (up to several hundred dynamical neutron star times scales).
The existence of this mini neutron star leaves a clear imprint on the
gravitational wave signal which thus can be used to probe the physics at
supra-nuclear densities.Comment: submitted to MNRAS, 23 pages, 16 figure
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A framework for evaluating image segmentation algorithms
The purpose of this paper is to describe a framework for evaluating image segmentation algorithms. Image segmentation consists of object recognition and delineation. For evaluating segmentation methods, three factors—precision (reliability), accuracy (validity), and efficiency (viability)—need to be considered for both recognition and delineation. To assess precision, we need to choose a figure of merit, repeat segmentation considering all sources of variation, and determine variations in figure of merit via statistical analysis. It is impossible usually to establish true segmentation. Hence, to assess accuracy, we need to choose a surrogate of true segmentation and proceed as for precision. In determining accuracy, it may be important to consider different 'landmark' areas of the structure to be segmented depending on the application. To assess efficiency, both the computational and the user time required for algorithm training and for algorithm execution should be measured and analyzed. Precision, accuracy, and efficiency factors have an influence on one another. It is difficult to improve one factor without affecting others. Segmentation methods must be compared based on all three factors, as illustrated in an example wherein two methods are compared in a particular application domain. The weight given to each factor depends on application
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