579 research outputs found
‘Exercise-Eating Linkage’ Mediated by Neuro-Endocrine Axis and the Relevance in Regulation of Appetite and Energy Balance for Prevention of Obesity
Estimating the Eddy Viscosity Profile from Velocity Spirals in the Ekman Boundary Layer
Final Form: December 18, 2014Turbulent mixing induced by tidal currents near the sea bottom plays a key role in coastal and shallow sea environments. Many attempts have been made to quantify turbulent mixing near the seabed, such as velocity microstructure measurements with microstructure profilers and turbulent Reynolds stress measurements using acoustic Doppler current profilers (ADCPs). This study proposes an alternative method in which the Ekman balance equations are solved with measured velocity spirals to estimate the eddy viscosity profile. Three schemes (schemes 1, 2, and 3) are described in this paper; schemes 1 and 2 were used in previous studies, while scheme 3 is newly proposed in the present study. The performance of the three schemes was tested using velocity spirals simulated with an idealized eddy viscosity profile, showing that scheme 2 is useful if the random measurement errors are small, while scheme 3 is useful when the errors in the Ekman balance are small. The performance was also evaluated using measured velocity spirals. This method utilizes velocity measured with standard ADCPs operated in normal modes, allowing for easier and more frequent quantifications of the mixing averaged over longer periods
Holographic storage of multiple coherence gratings in a Bose-Einstein condensate
We demonstrate superradiant conversion between a two-mode collective atomic
state and a single-mode light field in an elongated cloud of Bose-condensed
atoms. Two off-resonant write beams induce superradiant Raman scattering,
producing two independent coherence gratings with a different wave vector in
the cloud. By applying phase-matched read beams after a controllable delay, the
gratings can be selectively converted into the light field also in a
superradiant way. Due to the large cooperativity parameter and the small
velocity width of the condensate, a high conversion efficiency of % and
a long storage time of s were achieved.Comment: 5 pages, 4 figure
How does torsional rigidity affect the wrapping transition of a semiflexible chain around a spherical core?
We investigated the effect of torsional rigidity of a semiflexible chain on
the wrapping transition around a spherical core, as a model of nucleosome, the
fundamental unit of chromatin. Through molecular dynamics simulation, we show
that the torsional effect has a crucial effect on the chain wrapping around the
core under the topological constraints. In particular, the torsional stress (i)
induces the wrapping/unwrapping transition, and (ii) leads to a unique complex
structure with an antagonistic wrapping direction which never appears without
the topological constraints. We further examine the effect of the stretching
stress for the nucleosome model, in relation to the unique characteristic
effect of the torsional stress on the manner of wrapping
Complete temporal mode characterization of non-Gaussian states by dual homodyne measurement
Optical quantum states defined in temporal modes, especially non-Gaussian
states like photon-number states, play an important role in quantum computing
schemes. In general, the temporal-mode structures of these states are
characterized by one or more complex functions called temporal-mode functions
(TMFs). Although we can calculate TMF theoretically in some cases, experimental
estimation of TMF is more advantageous to utilize the states with high purity.
In this paper, we propose a method to estimate complex TMFs. This method can be
applied not only to arbitrary single-temporal-mode non-Gaussian states but also
to two-temporal-mode states containing two photons. This method is implemented
by continuous-wave (CW) dual homodyne measurement and doesn't need prior
information of the target states nor state reconstruction procedure. We
demonstrate this method by analyzing several experimentally created
non-Gaussian states
Temporal change in rock-magnetic properties of volcanic ashes ejected during a 1-year eruption event: a case study on the Aso Nakadake 2019-2020 eruption
We investigated temporal changes in the rock-magnetic properties of volcanic ash ejected from the Aso Nakadake volcano during a sequence of ash eruptions from 2019 to 2020. For 39 volcanic ash samples, magnetic hysteresis parameters, including saturation magnetization (M-s), saturation remanent magnetization (M-rs), coercivity (B-c), and coercivity of remanence (B-cr), were obtained. Curie temperature (T-c) of the samples was also estimated using thermomagnetic analyses. Titanium-rich and -poor titanomagnetites were the dominant magnetic minerals in the volcanic ash, of which the titanium-rich phase was dominant. Systematic magnetic measurements of the volcanic ash ejected during the 1-year eruption event indicate that temporal changes in the hysteresis parameters occurred throughout the event. These temporal changes suggest that the M-rs/M-s and B-c values of the volcanic ash increased considerably during several periods. The clear increases in M-rs/M-s and B-c, associated with the central peak in FORC diagrams, indicate that non-interacting single-domain grains increased. For these high M-rs/M-s and B-c samples, thermal demagnetizations of 3-axis IRM show that the low unblocking-temperature component up to 250-300 & DEG;C has apparently higher coercivity, suggesting that the above-mentioned, non-interacting single-domain grains are Ti-rich titanomagnetite. Interestingly, the high M-rs/M-s and B-c values were synchronous with observations of volcanic glow. These results suggest that changes in the magnetic properties of titanomagnetite grains in volcanic ash reflect changes in physical conditions from the vent to the conduit of the volcano
In-situ observation and multi-physics simulation of reactive melt Infiltration of silicon melt into SiC-C Preform
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Are water markets globally applicable?
Water scarcity is a global concern that necessitates a global perspective, but it is also the product of multiple regional issues that require regional solutions. Water markets constitute a regionally applicable non-structural measure to counter water scarcity that has received the attention of academics and policy-makers, but there is no global view on their applicability. We present the global distribution of potential nations and states where water markets could be instituted in a legal sense, by investigating 296 water laws internationally, with special reference to a minimum set of key rules: legalization of water reallocation, the separation of water rights and landownership, and the modification of the cancellation rule for non-use. We also suggest two additional globally distributed prerequisites and policy implications: the predictability of the available water before irrigation periods and public control of groundwater pumping throughout its jurisdiction
Schr\"odinger's cat in an optical sideband
We propose a method to subtract a photon from a double sideband mode of
continuous-wave light. The central idea is to use phase modulation as a
frequency sideband beamsplitter in the heralding photon subtraction scheme,
where a small portion of the sideband mode is downconverted to the carrier
frequency to provide a trigger photon. An optical Schr\"odinger's cat state is
created by applying the propesed method to a squeezed state at 500MHz sideband,
which is generated by an optical parametric oscillator. The Wigner function of
the cat state reconstructed from a direct homodyne measurement of the 500MHz
sideband modes shows the negativity of without any
loss corrections.Comment: 11 pages, 9 figure
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