21,839 research outputs found
Online Forum Thread Retrieval using Pseudo Cluster Selection and Voting Techniques
Online forums facilitate knowledge seeking and sharing on the Web. However,
the shared knowledge is not fully utilized due to information overload. Thread
retrieval is one method to overcome information overload. In this paper, we
propose a model that combines two existing approaches: the Pseudo Cluster
Selection and the Voting Techniques. In both, a retrieval system first scores a
list of messages and then ranks threads by aggregating their scored messages.
They differ on what and how to aggregate. The pseudo cluster selection focuses
on input, while voting techniques focus on the aggregation method. Our combined
models focus on the input and the aggregation methods. The result shows that
some combined models are statistically superior to baseline methods.Comment: The original publication is available at
http://www.springerlink.com/. arXiv admin note: substantial text overlap with
arXiv:1212.533
Thermal activation energy of 3D vortex matter in NaFe1-xCoxAs (x=0.01, 0.03 and 0.07) single crystals
We report on the thermally activated flux flow dependency on the doping
dependent mixed state in NaFe1-xCoxAs (x=0.01, 0.03, and 0.07) crystals using
the magnetoresistivity in the case of B//c-axis and B//ab-plane. It was found
clearly that irrespective of the doping ratio, magnetoresistivity showed a
distinct tail just above the Tc, offset associated with the thermally activated
flux flow (TAFF) in our crystals. Furthermore, in TAFF region the temperature
dependence of the activation energy follows the relation U(T, B)=U_0 (B)
(1-T/T_c )^q with q=1.5 in all studied crystals. The magnetic field dependence
of the activation energy follows a power law of U_0 (B)~B^(-{\alpha}) where the
exponent {\alpha} is changed from a low value to a high value at a crossover
field of B=~2T, indicating the transition from collective to plastic pinning in
the crystals. Finally, it is suggested that the 3D vortex phase is the dominant
phase in the low-temperature region as compared to the TAFF region in our
series samples
Pressure effects on the heavy-fermion antiferromagnet CeAuSb2
The f-electron compound CeAuSb2, which crystallizes in the ZrCuSi2-type
tetragonal structure, orders antiferromagnetically between 5 and 6.8 K, where
the antiferromagnetic transition temperature T_N depends on the occupancy of
the Au site. Here we report the electrical resistivity and heat capacity of a
high-quality crystal CeAuSb2 with T_N of 6.8 K, the highest for this compound.
The magnetic transition temperature is initially suppressed with pressure, but
is intercepted by a new magnetic state above 2.1 GPa. The new phase shows a
dome shape with pressure and coexists with another phase at pressures higher
than 4.7 GPa. The electrical resistivity shows a T^2 Fermi liquids behavior in
the complex magnetic state, and the residual resistivity and the T^2
resistivity coefficient increases with pressure, suggesting the possibility of
a magnetic quantum critical point at a higher pressure.Comment: 5 pages, 5 firure
Irrigation Technology Adoption in the Texas High Plains: A Real Options Approach
Water scarcity has been a significant issue for several decades in the Texas High Plains, with agriculture identified as the main activity contributing to this scarcity. To address this issue, much effort has been devoted to developing and encouraging adoption of sophisticated irrigation systems with high levels of water application efficiency, such as the low energy precision application (LEPA) system, subsurface drip irrigation (SDI), and variable rate irrigation (VRI). In this study, the economic feasibility of these irrigation systems is evaluated in cotton farming in the Texas High Plains using a real options approach. Results find that only the LEPA system is profitable under current conditions. The VRI system is profitable with high cotton prices (above $0.72/lb), while SDI is not profitable under any conditions explored.Resource /Energy Economics and Policy,
Rigidity of minimal submanifolds in hyperbolic space
We prove that if an -dimensional complete minimal submanifold in
hyperbolic space has sufficiently small total scalar curvature then has
only one end. We also prove that for such there exist no nontrivial
harmonic 1-forms on
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