9,929 research outputs found
Asynchronous Remote Medical Consultation for Ghana
Computer-mediated communication systems can be used to bridge the gap between
doctors in underserved regions with local shortages of medical expertise and
medical specialists worldwide. To this end, we describe the design of a
prototype remote consultation system intended to provide the social,
institutional and infrastructural context for sustained, self-organizing growth
of a globally-distributed Ghanaian medical community. The design is grounded in
an iterative design process that included two rounds of extended design
fieldwork throughout Ghana and draws on three key design principles (social
networks as a framework on which to build incentives within a self-organizing
network; optional and incremental integration with existing referral
mechanisms; and a weakly-connected, distributed architecture that allows for a
highly interactive, responsive system despite failures in connectivity). We
discuss initial experiences from an ongoing trial deployment in southern Ghana.Comment: 10 page
"Heterotic" Discrete Flavor Model
We present an extended 331 model with discrete flavor symmetry that
simultaneously explains the need to have exactly three generations and provides
acceptable quark and lepton masses and mixings. New fermionic states and gauge
bosons are predicted within the reach of the LHC. We discuss the relevance to
the 126 GeV scalar discovered at the LHC.Comment: 13 pages, v3: version to appear in PR
Descent methods for Nonnegative Matrix Factorization
In this paper, we present several descent methods that can be applied to
nonnegative matrix factorization and we analyze a recently developped fast
block coordinate method called Rank-one Residue Iteration (RRI). We also give a
comparison of these different methods and show that the new block coordinate
method has better properties in terms of approximation error and complexity. By
interpreting this method as a rank-one approximation of the residue matrix, we
prove that it \emph{converges} and also extend it to the nonnegative tensor
factorization and introduce some variants of the method by imposing some
additional controllable constraints such as: sparsity, discreteness and
smoothness.Comment: 47 pages. New convergence proof using damped version of RRI. To
appear in Numerical Linear Algebra in Signals, Systems and Control. Accepted.
Illustrating Matlab code is included in the source bundl
Radio Continuum Sources Associated with AB Aur
We present high angular resolution, high-sensitivity Very Large Array
observations at 3.6 cm of the Herbig Ae star AB Aur. This star is of interest
since its circumstellar disk exhibits characteristics that have been attributed
to the presence of an undetected low mass companion or giant gas planet. Our
image confirms the continuum emission known to exist in association with the
star, and detects a faint protuberance that extends about to its
SE. Previous theoretical considerations and observational results are
consistent with the presence of a companion to AB Aur with the separation and
position angle derived from our radio data. We also determine the proper motion
of AB Aur by comparing our new observations with data taken about 17 years ago
and find values consistent with those found by Hipparcos.Comment: 6 pages, 1 figur
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