1,978 research outputs found
Pentaquark states with the configuration in a simple model
We discuss the mass splittings for the -wave triply heavy pentaquark
states with the configuration which is a mirror
structure of . The latter configuration is related with the nature
of observed by the LHCb Collaboration. The considered pentaquark
masses are roughly estimated with a simple method. One finds that such states
are probably not narrow even if they do exist. This leaves room for molecule
interpretation for a state around the low-lying threshold of a doubly heavy
baryon and a heavy-light meson, e.g. , if it were observed. As a by
product, we conjecture that upper limits for the masses of the conventional
triply heavy baryons can be determined by the masses of the conventional doubly
heavy baryons.Comment: 19 pages, 1 figure, 10 tables; Version accepted by Eur. Phys. J.
Applications of Cluster Analysis and Pattern Recognition for Typhoon Hourly Rainfall Forecast
Noise suppression of on-chip mechanical resonators by chaotic coherent feedback
We propose a method to decouple the nanomechanical resonator in
optomechanical systems from the environmental noise by introducing a chaotic
coherent feedback loop. We find that the chaotic controller in the feedback
loop can modulate the dynamics of the controlled optomechanical system and
induce a broadband response of the mechanical mode. This broadband response of
the mechanical mode will cut off the coupling between the mechanical mode and
the environment and thus suppress the environmental noise of the mechanical
modes. As an application, we use the protected optomechanical system to act as
a quantum memory. It's shown that the noise-decoupled optomechanical quantum
memory is efficient for storing information transferred from coherent or
squeezed light
Exact Boundary Derivative Formulation for Numerical Conformal Mapping Method
Conformal mapping is a useful technique for handling irregular geometries when applying the finite difference method to solve partial differential equations. When the mapping is from a hyperrectangular region onto a rectangular region, a specific length-to-width ratio of the rectangular region that fitted the Cauchy-Riemann equations must be satisfied. In this research, a numerical integral method is proposed to find the specific length-to-width ratio. It is conventional to employ the boundary integral method (BIEM) to perform the conformal mapping. However, due to the singularity produced by the BIEM in seeking the derivatives on the boundaries, the transformation Jacobian determinants on the boundaries have to be evaluated at inner points instead of directly on the boundaries. This approximation is a source of numerical error. In this study, the transformed rectangular property and the Cauchy-Riemann equations are successfully applied to derive reduced formulations of the derivatives on the boundaries for the BIEM. With these boundary derivative formulations, the Jacobian determinants can be evaluated directly on the boundaries. Furthermore, the results obtained are more accurate than those of the earlier mapping method
Automatic Calibration of an Unsteady River Flow Model by Using Dynamically Dimensioned Search Algorithm
New Approach for Evaluation of a Watershed Ecosystem Service for Avoiding Reservoir Sedimentation and Its Economic Value: A Case Study from Ertan Reservoir in Yalong River, China
A model was established to simulate an ecosystem service of avoiding reservoir sedimentation and its economic value based on the process of sediment delivery in a watershed. The model included fabricating the watershed of the study reservoir. The sediment retention coefficient of different land cover types were used to simulate the spatial patterns of the annual quantity of the sediment that were prevented from entering the reservoir by the vegetation in each cell followed the flow path in watershed. The economic value of the ecosystem service in this model was determined by the marginal cost of reservoir desilting. This study took the Ertan reservoir as an example. The results showed that most eroded soil was intercepted by different types of ecosystems in the process of sediment delivery in a watershed. The region with a higher quantity of sediment retention was around the reservoir. The absolute quantity of average sediment retention in forestland was lower, so the sediment retention ability of forestland failed to be brought into fullest play in watershed
Evidence of Decreased Activity in Intermediate-Conductance Calcium-Activated Potassium Channels During Retinoic Acid–Induced Differentiation in Motor Neuron–Like NSC-34 Cells
Background/Aims: Intermediate-conductance Ca2+-activated K+ (IKCa; KCa3.1 or KCNN4) channels affect the behaviors of central neurons including motor neurons. The mechanism through which neuronal differentiation is related to the activity of these channels remains largely unclear. Methods: By using various molecular biology tools and electrophysiological measurements, we investigated possible changes in the activity of IKCa channels in a retinoic acid (RA)-induced differentiation process in motor neuron-like NSC-34 cells. Results: The protein and messenger RNA expression of KCa3.1 substantially diminished as NSC-34 cells were differentiated with low serum (1%) and 1 µM RA. In whole-cell current recordings, the density of delayed-rectifier K+ currents obtained from differentiated cells was elevated. However, the density of a ramp pulse-elicited K+ current that was sensitive to blockage by 1-((2-chlorophenyl) (diphenyl)methyl)-1H-pyrazole (TRAM-34)—an inhibitor of IKCa channels—was significantly higher in undifferentiated NSC-34 cells than in differentiated cells. In undifferentiated cells, the activity of IKCa channels was readily detected and the probability of channel openings was resistant to stimulation by diazoxide or suppression by verruculogen. Furthermore, this probability was increased by 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one or 9-phenanthrol and reduced by TRAM-34. The channel-opening probability decreased in RA-induced differentiated cells, whereas the single-channel conductance of IKCa channels did not differ between undifferentiated and differentiated cells. Moreover, the slow component of the mean closed time in these channels was significantly shorter in undifferentiated cells than in differentiated cells; however, the mean open time in the channel remained unchanged as cells were differentiated. Conclusion: RA-induced differentiation in neurons could exert a suppressive effect on the activity of IKCa channels
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