33,137 research outputs found
New method for critical failure prediction of complex systems
Rigorous analytical technique, called criticality determination methodology /or CD technique/ determines the probability that a given complex system will successfully achieve stated objectives. The CD technique identifies critical elements of the system by a failure mode and effects analysis
The bosonic Kondo effect
The Kondo effect is associated with the formation of a many-body ground state
that contains a quantum-mechanical entanglement between a (localized) fermion
and the free fermions. We show that a bosonic version of the Kondo effect can
occur in degenerate atomic Fermi gases near the Feshbach resonance. We also
discuss how this bosonic Kondo effect can be observed experimentally.Comment: 4 pages, 2 figures, some references added, some removed. More
comments adde
The Herschel view of the nebula around the luminous blue variable star AG Carinae
Far-infrared Herschel PACS imaging and spectroscopic observations of the
nebula around the luminous blue variable (LBV) star AG Car have been obtained
along with optical imaging in the Halpha+[NII] filter. In the infrared light,
the nebula appears as a clumpy ring shell that extends up to 1.2 pc with an
inner radius of 0.4 pc. It coincides with the Halpha nebula, but extends
further out. Dust modeling of the nebula was performed and indicates the
presence of large grains. The dust mass is estimated to be ~ 0.2 Msun. The
infrared spectrum of the nebula consists of forbidden emission lines over a
dust continuum. Apart from ionized gas, these lines also indicate the existence
of neutral gas in a photodissociation region that surrounds the ionized region.
The abundance ratios point towards enrichment by processed material. The total
mass of the nebula ejected from the central star amounts to ~ 15 Msun, assuming
a dust-to-gas ratio typical of LBVs. The abundances and the mass-loss rate were
used to constrain the evolutionary path of the central star and the epoch at
which the nebula was ejected, with the help of available evolutionary models.
This suggests an ejection during a cool LBV phase for a star of ~ 55 Msun with
little rotation.Comment: accepted for publication in A&
Implementing a Shared Dataspace Language on a Message-Based Multiprocessor
The term shared dataspace refers to the general class of models and languages in which the principal means of communication is a common, content-addressable data structure called a dataspace. This paper reports on progress we have made toward the development of prototype implementation of a shared dataspace language, Swarm, on a hypercube multiprocessor. The paper includes an informal overview of the Swarm language, describes the design organization of a transaction processing system which forms the kernels of a Swam implementation, and explains the algorithms implementing a subset of Swarm embedded in the language C
Phylogenetic relationships of haplolepideous mosses (Dicranidae) inferred from rps4 gene sequences
The haplolepideous mosses (Dicranidae) constitute a large group of ecologically and
morphologically diverse species recognised primarily by having peristome teeth with a
single row of cells on the dorsal surface
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