12,540 research outputs found
A novel evolutionary formulation of the maximum independent set problem
We introduce a novel evolutionary formulation of the problem of finding a
maximum independent set of a graph. The new formulation is based on the
relationship that exists between a graph's independence number and its acyclic
orientations. It views such orientations as individuals and evolves them with
the aid of evolutionary operators that are very heavily based on the structure
of the graph and its acyclic orientations. The resulting heuristic has been
tested on some of the Second DIMACS Implementation Challenge benchmark graphs,
and has been found to be competitive when compared to several of the other
heuristics that have also been tested on those graphs
Cultivo consorciado de manjericão em sistema de produção orgânico.
bitstream/item/65301/1/manjericao.pd
Biomass burning and urban air pollution over the Central Mexican Plateau
Observations during the 2006 dry season of highly elevated concentrations of cyanides in the atmosphere above Mexico City (MC) and the surrounding plains demonstrate that biomass burning (BB) significantly impacted air quality in the region. We find that during the period of our measurements, fires contribute more than half of the organic aerosol mass and submicron aerosol scattering, and one third of the enhancement in benzene, reactive nitrogen, and carbon monoxide in the outflow from the plateau. The combination of biomass burning and anthropogenic emissions will affect ozone chemistry in the MC outflow
Pastejo precoce de bezerros de raca leiteira nascidos em duas estacoes do ano.
bitstream/item/142976/1/2013.pd
Ultrahigh Transmission Optical Nanofibers
We present a procedure for reproducibly fabricating ultrahigh transmission
optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode
transmissions of 99.95 0.02%, which represents a loss from tapering of
2.6 10 dB/mm when normalized to the entire stretch. When
controllably launching the next family of higher-order modes on a fiber with
195 mm stretch, we achieve a transmission of 97.8 2.8%, which has a loss
from tapering of 5.0 10 dB/mm when normalized to the
entire stretch. Our pulling and transfer procedures allow us to fabricate
optical nanofibers that transmit more than 400 mW in high vacuum conditions.
These results, published as parameters in our previous work, present an
improvement of two orders of magnitude less loss for the fundamental mode and
an increase in transmission of more than 300% for higher-order modes, when
following the protocols detailed in this paper. We extract from the
transmission during the pull, the only reported spectrogram of a fundamental
mode launch that does not include excitation to asymmetric modes; in stark
contrast to a pull in which our cleaning protocol is not followed. These
results depend critically on the pre-pull cleanliness and when properly
following our pulling protocols are in excellent agreement with simulations.Comment: 32 pages, 10 figures, accepted to AIP Advance
Metodologia para determinação da peroxidase e da polifenol oxidase em plantas.
bitstream/item/31616/1/comunicado87.pd
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