4,236 research outputs found
SciRecSys: A Recommendation System for Scientific Publication by Discovering Keyword Relationships
In this work, we propose a new approach for discovering various relationships
among keywords over the scientific publications based on a Markov Chain model.
It is an important problem since keywords are the basic elements for
representing abstract objects such as documents, user profiles, topics and many
things else. Our model is very effective since it combines four important
factors in scientific publications: content, publicity, impact and randomness.
Particularly, a recommendation system (called SciRecSys) has been presented to
support users to efficiently find out relevant articles
Localized ferromagnetic resonance force microscopy in permalloy-cobalt films
We report Ferromagnetic Resonance Force Microscopy (FMRFM) experiments on a
justaposed continuous films of permalloy and cobalt. Our studies demonstrate
the capability of FMRFM to perform local spectroscopy of different
ferromagnetic materials. Theoretical analysis of the uniform resonance mode
near the edge of the film agrees quantitatively with experimental data. Our
experiments demonstrate the micron scale lateral resolution in determining
local magnetic properties in continuous ferromagnetic samples.Comment: 7 pages, 3 figure
Mapping local optical densities of states in silicon photonic structures with nanoscale electron spectroscopy
Relativistic electrons in a structured medium generate radiative losses such
as Cherenkov and transition radiation that act as a virtual light source,
coupling to the photonic densities of states. The effect is most pronounced
when the imaginary part of the dielectric function is zero, a regime where in a
non-retarded treatment no loss or coupling can occur. Maps of the resultant
energy losses as a sub-5nm electron probe scans across finite waveguide
structures reveal spatial distributions of optical modes in a spectral domain
ranging from near-infrared to far ultraviolet.Comment: 18 pages, 4 figure
Ascorbate depletion increases growth and metastasis of melanoma cells in vitamin C deficient mice
Aim: Our main objective was to determine the effect of ascorbate supplementation in mice unable to synthesize ascorbic acid (gulo KO) when challenged with murine B16FO cancer cells. Methods: Gulo KO female mice 36–40 weeks of age were deprived of or maintained on ascorbate in food and water for 4 weeks prior to subcutaneous injection of 2.5×106 B16FO murine melanoma cells in the right flank of mice. A control group of wild type mice were also injected with the melanoma cells and maintained on a regular murine diet. Mice were continued on their respective diets for another 2 weeks after injection. The mice were then sacrificed, blood was drawn and their tumors were measured, excised and processed for histology. Results: Mean weight of animals decreased significantly (30%, p < 0.0001) in the ascorbate-restricted group but increased slightly, but insignificantly, in the ascorbate-supplemented group. The mean tumor weight in ascorbate supplemented mice was significantly reduced (by 64%, p = 0.004) compared to tumor weight in ascorbate-deprived gulo mice. The mean tumor weight of wild type mice did not differ significantly from the ascorbate-supplemented mice. Gulo KO mice supplemented with ascorbate developed smaller tumors with more collagen encapsulation and fibrous capsule interdigitation, while gulo KO mice deprived of ascorbate hosted large tumors with poorly defined borders, showing more necrosis and mitosis. Ascorbate supplementation of gulo KO mice resulted in profoundly decreased serum inflammatory cytokine IL-6 (90% decrease, p = 0.04) and IL-1β (62% decrease) compared to the levels in gulo KO mice deprived of ascorbate. Conclusion: Ascorbate supplementation modulated tumor growth and inflammatory cytokine secretion as well as enhanced encapsulation of tumors in scorbutic mice
Interstellar absorptions and shocked clouds towards supernova remnant RX J0852.0-4622
We present results of survey of interstellar absorptions towards supernova
remnant (SNR) RX J0852.0-4622. The distribution of KI absorbers along the
distance of the background stars is indicative of a local region (d<600pc)
strongly depopulated by KI line-absorbing clouds. This fact is supported by the
behavior of the interstellar extinction. We find four high-velocity CaII
components with velocities of >100km/s towards three stars and identify them
with shocked clouds of Vela SNR. We reveal and measure acceleration of two
shocked clouds at the approaching and receding sides of Vela SNR along the same
sight line. The clouds acceleration, velocity, and CaII column density are used
to probe cloud parameters. The total hydrogen column density of both
accelerating clouds is found to be similar (~6*10^{17} cm) which
indicates that possibly there is a significant amount of small-size clouds in
the vicinity of Vela SNR.Comment: accepted in MNRA
Spin Bose Glass Phase in Bilayer Quantum Hall Systems at
We develop an effective spin theory to describe magnetic properties of the
Quantum Hall bilayer systems. In the absence of disorder this theory
gives quantitative agreement with the results of microscopic Hartree-Fock
calculations, and for finite disorder it predicts the existence of a novel spin
Bose glass phase. The Bose glass is characterized by the presence of domains of
canted antiferromagnetic phase with zero average antiferromagnetic order and
short range mean antiferromagnetic correlations. It has infinite
antiferromagnetic transverse susceptibility, finite longitudinal spin
susceptibility and specific heat linear in temperature. Transition from the
canted antiferromagnet phase to the spin Bose glass phase is characterized by a
universal value of the longitudinal spin conductance.Comment: 4 pages, 4 eps figure
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