24,573 research outputs found
Rescattering effects in B_{u,d,s}(bar) to D P, D(bar) P decays
We study quasi-elastic rescattering effects in B_{u,d,s}(bar) to DP, D(bar)P
decays, where P is a light pseudoscalar. The updated measurements of
B_{u,d}(bar) to DP decays are used to extract the effective Wilson coefficients
a^{eff}_1 ~ 0.90, a^{eff}_2 ~ 0.23, three strong phases delta ~ 53 degree,
theta ~ 18 degree, sigma ~ -88 degree, and the mixing angle tau ~ 9 degree.
This information is used to predict rates of nineteen B_{s}(bar) to DP and
B_{u,d,s}(bar) to D(bar)P decay modes, including modes of interests in the
gamma/phi_3 program. Many decay rates are found to be enhanced. In particular,
the B_s(bar) to D0 K0 rate is predicted to be 8\times 10^{-4}, which could be
measured soon. The rescattering effects on the corresponding B_{u,d,s}(bar) to
D(bar)P, DP amplitude ratios r_B, r_{B_s}, and the relative strong phases
delta_B, delta_{B_s} are studied. Although the decay rates are enhanced in most
cases, r_{B,B_s} values are similar to factorization expectation.Comment: 16 page
Spin-current injection and detection in strongly correlated organic conductor
Spin-current injection into an organic semiconductor
film induced by the spin
pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in
the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage
signal was found to appear in the
film.
Magnetic-field-angle dependence measurements indicate that the voltage signal
is governed by the inverse spin Hall effect in
. We found that the
voltage signal in the /YIG
system is critically suppressed around 80 K, around which magnetic and/or glass
transitions occur, implying that the efficiency of the spin-current injection
is suppressed by fluctuations which critically enhanced near the transitions
Fermi resonance-algebraic model for molecular vibrational spectra
A Fermi resonance-algebraic model is proposed for molecular vibrations, where
a U(2) algebra is used for describing the vibrations of each bond, and Fermi
resonances between stretching and bending modes are taken into account. The
model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to
fit the recently observed vibrational spectrum of the water molecule and arsine
(AsH_3), respectively, and results are compared with those of other models.
Calculations show that algebraic approaches can be used as an effective method
for describing molecular vibrations with small standard deviations
Entanglement detection beyond the CCNR criterion for infinite-dimensions
In this paper, in terms of the relation between the state and the reduced
states of it, we obtain two inequalities which are valid for all separable
states in infinite-dimensional bipartite quantum systems. One of them provides
an entanglement criterion which is strictly stronger than the computable
cross-norm or realignment (CCNR) criterion.Comment: 11 page
Unsupervised Feature Selection with Adaptive Structure Learning
The problem of feature selection has raised considerable interests in the
past decade. Traditional unsupervised methods select the features which can
faithfully preserve the intrinsic structures of data, where the intrinsic
structures are estimated using all the input features of data. However, the
estimated intrinsic structures are unreliable/inaccurate when the redundant and
noisy features are not removed. Therefore, we face a dilemma here: one need the
true structures of data to identify the informative features, and one need the
informative features to accurately estimate the true structures of data. To
address this, we propose a unified learning framework which performs structure
learning and feature selection simultaneously. The structures are adaptively
learned from the results of feature selection, and the informative features are
reselected to preserve the refined structures of data. By leveraging the
interactions between these two essential tasks, we are able to capture accurate
structures and select more informative features. Experimental results on many
benchmark data sets demonstrate that the proposed method outperforms many state
of the art unsupervised feature selection methods
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High Sensitivity Hot-wire based Wind Velocity Sensor using Co-doped Fiber and Fiber Bragg Grating for use in mining applications
In this paper, a mathematical model of the temperature distribution in a fiber-optic version of the familiar 'hot-wire' wind velocity sensor has been established and a practical sensor device realized and investigated for use in coal mining applications. The relationship between the dynamic measurement range, the sensitivity, the sensor probe surface heat transfer coefficient and the wind speed (in the region where the sensor probe is located) has been investigated. The veracity of the predicted performance of the fiber-optic hot-wire mathematical model has then been verified by experiment. The sensitivity of the sensor probe to wind velocity was measured across several wind velocity ranges to be ∼1500pm per unit m/s wind velocity (in the range of 0 - 0.5 m/s), ∼330pm per unit m/s in the range 0.5 - 2 m/s and ∼50pm per unit m/s in the range of 2.0 - 4.5 m/s
and the tree amplitude in
The recently-observed decay is expected to proceed
mainly by means of a tree amplitude in the factorization limit: , . Under this assumption, we predict the
corresponding contribution of the tree amplitude to . We
indicate the needed improvements in data that will allow a useful estimate of
this amplitude with errors comparable to those accompanying other methods.
Since the factorization hypothesis for this process goes beyond that proved in
most approaches, we also discuss independent tests of this hypothesis.Comment: 7 pages, LaTeX, 1 figure, to be submitted to Phys. Rev. D (Brief
Reports
Spectroscopic observations of a flare-related coronal jet
Coronal jets are ubiquitous in active regions (ARs) and coronal holes. In
this paper, we study a coronal jet related to a C3.4 circular-ribbon flare in
active region 12434 on 2015 October 16. Two minifilaments were located under a
3D fan-spine structure before flare. The flare was generated by the eruption of
one filament. The kinetic evolution of the jet was divided into two phases: a
slow rise phase at a speed of 131 km s and a fast rise phase at a
speed of 363 km s in the plane-of-sky. The slow rise phase may
correspond to the impulsive reconnection at the breakout current sheet. The
fast rise phase may correspond to magnetic reconnection at the flare current
sheet. The transition between the two phases occurred at 09:00:40 UT. The
blueshifted Doppler velocities of the jet in the Si {\sc iv} 1402.80 {\AA} line
range from -34 to -120 km s. The accelerated high-energy electrons are
composed of three groups. Those propagating upward along open field generate
type \textrm{III} radio bursts, while those propagating downward produce HXR
emissions and drive chromospheric condensation observed in the Si {\sc iv}
line. The electrons trapped in the rising filament generate a microwave burst
lasting for 40 s. Bidirectional outflows at the base of jet are manifested
by significant line broadenings of the Si {\sc iv} line. The blueshifted
Doppler velocities of outflows range from -13 to -101 km s. The
redshifted Doppler velocities of outflows range from 17 to 170 km
s. Our multiwavelength observations of the flare-related jet are in
favor of the breakout jet model and are important for understanding the
acceleration and transport of nonthermal electrons.Comment: 11 pages, 13 figures, accepted for publication in A&
Tripartite phase separation of two signal effectors with vesicles priming B cell responsiveness.
Antibody-mediated immune responses rely on antigen recognition by the B cell antigen receptor (BCR) and the proper engagement of its intracellular signal effector proteins. Src homology (SH) 2 domain-containing leukocyte protein of 65 kDa (SLP65) is the key scaffold protein mediating BCR signaling. In resting B cells, SLP65 colocalizes with Cbl-interacting protein of 85 kDa (CIN85) in cytoplasmic granules whose formation is not fully understood. Here we show that effective B cell activation requires tripartite phase separation of SLP65, CIN85, and lipid vesicles into droplets via vesicle binding of SLP65 and promiscuous interactions between nine SH3 domains of the trimeric CIN85 and the proline-rich motifs (PRMs) of SLP65. Vesicles are clustered and the dynamical structure of SLP65 persists in the droplet phase in vitro. Our results demonstrate that phase separation driven by concerted transient interactions between scaffold proteins and vesicles is a cellular mechanism to concentrate and organize signal transducers
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