1,834 research outputs found
Strong enhancement of chlorophyll a concentration by a weak typhoon
Recent studies demonstrate that chlorophyll a (chl a) concentrations in the
surface ocean can be significantly enhanced due to typhoons. The present study
investigated chl a concentrations in the middle of the South China Sea (SCS)
from 1997-2007. Only the Category1 (minimal) Typhoon Hagibis (2007) had a
notable effect on the chl a concentrations. Typhoon Hagibis had a strong
upwelling potential due to its location near the equator, and the forcing time
of the typhoon (>82 h) was much longer than the geostrophic adjustment time
(~63 h). The higher upwelling velocity and the longer forcing time increased
the depth of the mixed-layer, which consequently induced a strong phytoplankton
bloom that accounted for about 30% of the total annual chl a concentration in
the middle of the SCS. The implication is that the forcing time of a typhoon
should be long enough to establish a strong upwelling and consequently for the
induction of significant upper ocean responses.Comment: Typhoon-Ocean Environment interaction
Intertwined fractional quantum anomalous Hall states and charge density waves
Motivated by the recent experimental breakthrough on the observation of the
fractional quantum anomalous Hall (FQAH) effects in semiconductor and graphene
moir\'{e} materials, we explore the rich physics associated with the
coexistence of FQAH effect and the charge density wave (CDW) order that
spontaneously breaks the translation symmetry. We refer to a state with both
properties as "FQAH-crystal". We show that the interplay between FQAH effect
and CDW can lead to a rich phase diagram including multiple topological phases
and topological quantum phase transitions at the same moir\'e filling. In
particular, we demonstrate the possibility of direct quantum phase transitions
from a FQAH-crystal with Hall conductivity to a trivial CDW
insulator with , and more interestingly, to a QAH-crystal with
.Comment: 9 page
Inversion formula of multifractal energy dissipation in 3D fully developed turbulence
The concept of inverse statistics in turbulence has attracted much attention
in the recent years. It is argued that the scaling exponents of the direct
structure functions and the inverse structure functions satisfy an inversion
formula. This proposition has already been verified by numerical data using the
shell model. However, no direct evidence was reported for experimental three
dimensional turbulence. We propose to test the inversion formula using
experimental data of three dimensional fully developed turbulence by
considering the energy dissipation rates in stead of the usual efforts on the
structure functions. The moments of the exit distances are shown to exhibit
nice multifractality. The inversion formula between the direct and inverse
exponents is then verified.Comment: 3 RevTex pages including 3 eps figure
Low-energy Scattering of System and the Resonance-like Structure
In this paper, low-energy scattering of the meson
system is studied within L\"uscher's finite-size formalism using
twisted mass gauge field configurations. With three different pion mass values,
the -wave threshold scattering parameters, namely the scattering length
and the effective range , are extracted in channel. Our
results indicate that, in this particular channel, the interaction between the
two vector charmed mesons is weakly repulsive in nature hence do not support
the possibility of a shallow bound state for the two mesons, at least for the
pion mass values being studied. This study provides some useful information on
the nature of the newly discovered resonance-like structure
observed in various experiments.Comment: 11 pages, 6 figures. arXiv admin note: substantial text overlap with
arXiv:1403.131
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