86,272 research outputs found
Social reference: Aggregating online usage of scientific literature in CiteULike for clustering academic resources
Citation-based methods have been widely studied and employed for clustering academic resources and mapping science. Although effective, these methods suffer from citation delay. In this study, we extend reference and citation analysis to a broader notion from social perspective. We coin the term "social reference" to refer to the references of literatures in social academic web environment. We propose clustering methods using social reference information from CiteULike. We experiment for journal clustering and author clustering using social reference and compare with citation-based methods. Our experiments indicate: first, social reference implies connections among literatures which are as effective as citation in clustering academic resources; second, in practical settings, social reference-based clustering methods are not as effective as citation-based ones due to the sparseness of social reference data, but they can outperform in clustering new resources that have few citation. © 2011 Authors
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Dimer models from mirror symmetry and quivering amoebae
Dimer models are 2-dimensional combinatorial systems that have been shown to encode the gauge groups, matter content and tree-level superpotential of the world-volume quiver gauge theories obtained by placing D3-branes at the tip of a singular toric Calabi-Yau cone. In particular the dimer graph is dual to the quiver graph. However, the string theoretic explanation of this was unclear. In this paper we use mirror symmetry to shed light on this: the dimer models live on a T^2 subspace of the T^3 fiber that is involved in mirror symmetry and is wrapped by D6-branes. These D6-branes are mirror to the D3-branes at the singular point, and geometrically encode the same quiver theory on their world-volume
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Bioinspired Multifunctional Anti-icing Hydrogel
The recent anti-icing strategies in the state of the art mainly focused on three aspects: inhibiting ice nucleation, preventing ice propagation, and decreasing ice adhesion strength. However, it is has proved difficult to prevent ice nucleation and propagation while decreasing adhesion simultaneously, due to their highly distinct, even contradictory design principles. In nature, anti-freeze proteins (AFPs) offer a prime example of multifunctional integrated anti-icing materials that excel in all three key aspects of the anti-icing process simultaneously by tuning the structures and dynamics of interfacial water. Here, inspired by biological AFPs, we successfully created a multifunctional anti-icing material based on polydimethylsiloxane-grafted polyelectrolyte hydrogel that can tackle all three aspects of the anti-icing process simultaneously. The simplicity, mechanical durability, and versatility of these smooth hydrogel surfaces make it a promising option for a wide range of anti-icing applications
Radiance and Doppler shift distributions across the network of the quiet Sun
The radiance and Doppler-shift distributions across the solar network provide
observational constraints of two-dimensional modeling of transition-region
emission and flows in coronal funnels. Two different methods, dispersion plots
and average-profile studies, were applied to investigate these distributions.
In the dispersion plots, we divided the entire scanned region into a bright and
a dark part according to an image of Fe xii; we plotted intensities and Doppler
shifts in each bin as determined according to a filtered intensity of Si ii. We
also studied the difference in height variations of the magnetic field as
extrapolated from the MDI magnetogram, in and outside network. For the
average-profile study, we selected 74 individual cases and derived the average
profiles of intensities and Doppler shifts across the network. The dispersion
plots reveal that the intensities of Si ii and C iv increase from network
boundary to network center in both parts. However, the intensity of Ne viii
shows different trends, namely increasing in the bright part and decreasing in
the dark part. In both parts, the Doppler shift of C iv increases steadily from
internetwork to network center. The average-profile study reveals that the
intensities of the three lines all decline from the network center to
internetwork region. The binned intensities of Si ii and Ne viii have a good
correlation. We also find that the large blue shift of Ne viii does not
coincide with large red shift of C iv. Our results suggest that the network
structure is still prominent at the layer where Ne viii is formed in the quiet
Sun, and that the magnetic structures expand more strongly in the dark part
than in the bright part of this quiet Sun region.Comment: 10 pages,9 figure
Finite Symmetry of Leptonic Mass Matrices
We search for possible symmetries present in the leptonic mixing data from
SU(3) subgroups of order up to 511. Theoretical results based on symmetry are
compared with global fits of experimental data in a chi-squared analysis,
yielding the following results. There is no longer a group that can produce all
the mixing data without a free parameter, but a number of them can accommodate
the first or the second column of the mixing matrix. The only group that fits
the third column is . It predicts and
, in good agreement with experimental results.Comment: Version to appear in Physical Review
NIR Luminosity Function of Galaxies in Close Major-Merger Pairs and Mass Dependence of Merger Rate
A sample of close major-merger pairs (projected separation kpc, band magnitude difference mag) is selected from the matched 2MASS-2dFGRS catalog of Cole et al.
(2001). The pair primaries are brighter than mag. After
corrections for various biases, the comparison between counts in the paired
galaxy sample and counts in the parent sample shows that for the local `M*
galaxies' sampled by flux limited surveys, the fraction of galaxies in the
close major-merger pairs is 1.70. Using 38 paired galaxies in the
sample, a band luminosity function (LF) is calculated. This is the
first unbiased LF for a sample of objectively defined interacting/merging
galaxies in the local universe, while all previously determined LFs of paired
galaxies are biased by mistreating paired galaxies as singles. A stellar mass
function (MF) is translated from the LF. Compared to the LF/MF of 2MASS
galaxies, a differential pair fraction function is derived. The results suggest
a trend in the sense that less massive galaxies may have lower chance to be
involved in close major-merger pairs than more massive galaxies. The algorithm
presented in this paper can be easily applied to much larger samples of 2MASS
galaxies with redshifts in near future.Comment: Accepted by ApJL, 16 pages, 2 figure
The relationship between two flavors of oblivious transfer at the quantum level
Though all-or-nothing oblivious transfer and one-out-of-two oblivious
transfer are equivalent in classical cryptography, we here show that due to the
nature of quantum cryptography, a protocol built upon secure quantum
all-or-nothing oblivious transfer cannot satisfy the rigorous definition of
quantum one-out-of-two oblivious transfer.Comment: 4 pages, no figur
A cusp electron gun for millimeter wave gyrodevices
The experimental results of a thermionic cusp electron gun, to drive millimeter and submillimeter wave harmonic gyrodevices, are reported in this paper. Using a "smooth" magnetic field reversal formed by two coils this gun generated an annular-shaped, axis-encircling electron beam with 1.5 A current, and an adjustable velocity ratio alpha of up to 1.56 at a beam voltage of 40 kV. The beam cross-sectional shape and transported beam current were measured by a witness plate technique and Faraday cup, respectively. These measured results were found to be in excellent agreement with the simulated results using the three-dimensional code MAGIC
Deterministic Quantum Key Distribution Using Gaussian-Modulated Squeezed States
A continuous variable ping-pong scheme, which is utilized to generate
deterministically private key, is proposed. The proposed scheme is implemented
physically by using Gaussian-modulated squeezed states. The deterministic way,
i.e., no basis reconciliation between two parties, leads a two-times efficiency
comparing to the standard quantum key distribution schemes. Especially, the
separate control mode does not need in the proposed scheme so that it is
simpler and more available than previous ping-pong schemes. The attacker may be
detected easily through the fidelity of the transmitted signal, and may not be
successful in the beam splitter attack strategy.Comment: 7 pages, 4figure
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