193,314 research outputs found
Advancing Climate Change Research and Hydrocarbon Leak Detection : by Combining Dissolved Carbon Dioxide and Methane Measurements with ADCP Data
With the emergence of largescale, comprehensive environmental monitoring projects, there is an increased need to combine state-of-the art technologies to address complicated problems such as ocean acidifi cation and hydrocarbon leak
detection
Detection of flux emergence, splitting, merging, and cancellation of network field. I Splitting and Merging
Frequencies of magnetic patch processes on supergranule boundary, namely flux
emergence, splitting, merging, and cancellation, are investigated through an
automatic detection. We use a set of line of sight magnetograms taken by the
Solar Optical Telescope (SOT) on board Hinode satellite. We found 1636 positive
patches and 1637 negative patches in the data set, whose time duration is 3.5
hours and field of view is 112" \times 112". Total numbers of magnetic
processes are followed: 493 positive and 482 negative splittings, 536 positive
and 535 negative mergings, 86 cancellations, and 3 emergences. Total numbers of
emergence and cancellation are significantly smaller than those of splitting
and merging. Further, frequency dependences of merging and splitting processes
on flux content are investigated. Merging has a weak dependence on flux content
only with a power- law index of 0.28. Timescale for splitting is found to be
independent of parent flux content before splitting, which corresponds to \sim
33 minutes. It is also found that patches split into any flux contents with a
same probability. This splitting has a power-law distribution of flux content
with an index of -2 as a time independent solution. These results support that
the frequency distribution of flux content in the analyzed flux range is
rapidly maintained by merging and splitting, namely surface processes. We
suggest a model for frequency distributions of cancellation and emergence based
on this idea.Comment: 32 pages, 10 figures, 1 table, accepted to Ap
Detecting entanglement of random states with an entanglement witness
The entanglement content of high-dimensional random pure states is almost
maximal, nevertheless, we show that, due to the complexity of such states, the
detection of their entanglement using witness operators is rather difficult. We
discuss the case of unknown random states, and the case of known random states
for which we can optimize the entanglement witness. Moreover, we show that
coarse graining, modeled by considering mixtures of m random states instead of
pure ones, leads to a decay in the entanglement detection probability
exponential with m. Our results also allow to explain the emergence of
classicality in coarse grained quantum chaotic dynamics.Comment: 14 pages, 4 figures; minor typos correcte
Testing metric-affine f(R)-gravity by relic scalar gravitational waves
We discuss the emergence of scalar gravitational waves in metric-affine
f(R)-gravity. Such a component allows to discriminate between metric and
metric-affine theories The intrinsic meaning of this result is that the
geodesic structure of the theory can be discriminated. We extend the formalism
of cross correlation analysis, including the additional polarization mode, and
calculate the detectable energy density of the spectrum for cosmological relic
gravitons. The possible detection of the signal is discussed against
sensitivities of VIRGO, LIGO and LISA interferometers.Comment: 12 pages, 4 figure
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