28,022 research outputs found
Semantic Relation Classification via Convolutional Neural Networks with Simple Negative Sampling
Syntactic features play an essential role in identifying relationship in a
sentence. Previous neural network models often suffer from irrelevant
information introduced when subjects and objects are in a long distance. In
this paper, we propose to learn more robust relation representations from the
shortest dependency path through a convolution neural network. We further
propose a straightforward negative sampling strategy to improve the assignment
of subjects and objects. Experimental results show that our method outperforms
the state-of-the-art methods on the SemEval-2010 Task 8 dataset
Electric Character of Strange Stars
Using the Thomas-Fermi model, we investigated the electric characteristics of
a static non-magnetized strange star without crust in this paper. The exact
solutions of electron number density and electric field above the quark surface
are obtained. These results are useful if we are concerned about physical
processes near the quark matter surfaces of strange stars.Comment: 4 pages, 2 figures, LaTeX, Published in Chinese Physics Letters,
Vol.16, p.77
Too massive neutron stars: The role of dark matter?
The maximum mass of a neutron star is generally determined by the equation of
state of the star material. In this study, we take into account dark matter
particles, assumed to behave like fermions with a free parameter to account for
the interaction strength among the particles, as a possible constituent of
neutron stars. We find dark matter inside the star would soften the equation of
state more strongly than that of hyperons, and reduce largely the maximum mass
of the star. However, the neutron star maximum mass is sensitive to the
particle mass of dark matter, and a very high neutron star mass larger than 2
times solar mass could be achieved when the particle mass is small enough. Such
kind of dark-matter- admixed neutron stars could explain the recent measurement
of the Shapiro delay in the radio pulsar PSR J1614-2230, which yielded a
neutron star mass of 2 times solar mass that may be hardly reached when
hyperons are considered only, as in the case of the microscopic Brueckner
theory. Furthermore, in this particular case, we point out that the dark matter
around a neutron star should also contribute to the mass measurement due to its
pure gravitational effect. However, our numerically calculation illustrates
that such contribution could be safely ignored because of the usual diluted
dark matter environment assumed. We conclude that a very high mass measurement
of about 2 times solar mass requires a really stiff equation of state in
neutron stars, and find a strong upper limit (<= 0.64 GeV) for the particle
mass of non-self- annihilating dark matter based on the present model.Comment: Astroparticle Physics (2012) in Pres
Tris(2,2′-bipyridyl-κ2 N,N′)copper(II) sulfate 7.5-hydrate
The title compound, [Cu(C10H8N2)3]SO4·7.5H2O, is a six-coordinate copper(II) complex with a slightly elongated octahedral coordination geometry. The pyridyl rings of the three bipyridyl ligands are not coplanar, making dihedral angels of 9.5 (5), 5.2 (4) and 5.8 (5)°. In the crystal, several O—H⋯O and C—H⋯O hydrogen-bonding interactions are observed due to the existance of a large number of water molecules and the sulfate dianions
Primary retroperitoneal carcinosarcoma in a child: a case report
Carcinosarcoma is a rare biphasic malignancy consisting of intermixed epithelial and mesenchymal elements. Carcinosarcoma is particularly rare among children. We accepted a 7 year old patient with retroperitoneal carcinosarcoma. The tumor was totally resected and no recurrence is found 11 months after operation. Literatures has been reviewed and there are few reports of primary retroperitoneal carcinosarcoma in children up to date. So we report the patient's clinical character, surgical resection, pathological and immunohistochemical analysis
Instanton Effects in QCD Sum Rules for the Hybrid
In this paper, we study instanton contributions to the correlator of the
hybrid current . These contributions
are then included in a QCD sum-rule analysis of the isoscalar hybrid
mass. We find a mass at 1.83 GeV for the hybrid.
However, for the hybrid, we find the sum rules are unstable. We also
study non-zero width effects, which affect the mass prediction. The mixing
effects between these two states are studied and we find QCD sum rules support
the existence of a flavor singlet hybrid with mass at around 1.9 GeV. Finally,
we study the mixing effects between hybrid and glueball currents. The mixing
between the () and the glueball causes
two states, one in the region 1.4-1.8 GeV(1.4-2.2 GeV), and the other in the
range 1.8-2.2 GeV(2.2-2.6 GeV).Comment: 12 pages, revised versio
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