1,933 research outputs found
Chiral perturbation theory for pentaquark baryons and its applications
We construct a chiral lagrangian for pentaquark baryons assuming that the
recently found Theta^+ (1540) state belongs to an antidecuplet of SU(3) flavor
symmetry with J^P = (1/2)^(+-). We derive the Gell-Mann-Okubo formulae for the
antidecuplet baryon masses, and a possible mixing between the antidecuplet and
the pentaquark octet. Then we calculate the cross sections for pi^- p -> K^-
Theta^+ and gamma n -> K^- Theta^+ using our chiral lagrangian. The resulting
amplitudes respect the underlying chiral symmetry of QCD correctly. We also
describe how to include the light vector mesons in the chiral lagrangian.Comment: 4 page
Trap-Based Pest Counting: Multiscale and Deformable Attention CenterNet Integrating Internal LR and HR Joint Feature Learning
Pest counting, which predicts the number of pests in the early stage, is very
important because it enables rapid pest control, reduces damage to crops, and
improves productivity. In recent years, light traps have been increasingly used
to lure and photograph pests for pest counting. However, pest images have a
wide range of variability in pest appearance owing to severe occlusion, wide
pose variation, and even scale variation. This makes pest counting more
challenging. To address these issues, this study proposes a new pest counting
model referred to as multiscale and deformable attention CenterNet
(Mada-CenterNet) for internal low-resolution (LR) and high-resolution (HR)
joint feature learning. Compared with the conventional CenterNet, the proposed
Mada-CenterNet adopts a multiscale heatmap generation approach in a two-step
fashion to predict LR and HR heatmaps adaptively learned to scale variations,
that is, changes in the number of pests. In addition, to overcome the pose and
occlusion problems, a new between-hourglass skip connection based on deformable
and multiscale attention is designed to ensure internal LR and HR joint feature
learning and incorporate geometric deformation, thereby resulting in an
improved pest counting accuracy. Through experiments, the proposed
Mada-CenterNet is verified to generate the HR heatmap more accurately and
improve pest counting accuracy owing to multiscale heatmap generation, joint
internal feature learning, and deformable and multiscale attention. In
addition, the proposed model is confirmed to be effective in overcoming severe
occlusions and variations in pose and scale. The experimental results show that
the proposed model outperforms state-of-the-art crowd counting and object
detection models
Early-Bird or Last-Minute? The Impact of Mobile Channel Adoption on Purchasing Behavior
With the introduction of mobile technology, user behavior has been changed. One of the most representative features of mobile channels is that it enables users to access services regardless of time and place. The mobile channel is expected to enhance the flexibility of users. We examine whether there is a difference in purchase behavior between users who adopted mobile channels and those who did not, in a context where purchase time is limited and early purchase gives potential financial merit, using a large dataset from high-speed railway service in Korea. An interesting issue is whether mobile channel makes users purchase earlier and increase the chance to get discounts. Our results using difference-in-differences estimation with propensity score matching show that people who adopted mobile channel purchase tickets later on average and at a higher price than those who did not adopt mobile channel
On the origin of the hump structure in the in-plane optical conductivity of high Tc cuprates based on a SU(2) slave-boson theory
An improved version of SU(2) slave-boson approach is applied to study the
in-plane optical conductivity of the two dimensional systems of high Tc
cuprates. We investigate the role of fluctuations of both the phase and
amplitude of order parameters on the (Drude) peak-dip-hump structure in the
in-plane conductivity as a function of hole doping concentration and
temperature. The mid-infrared(MIR) hump in the in-plane optical conductivity is
shown to originate from the antiferromagnetic spin fluctuations of short
range(the amplitude fluctuations of spin singlet pairing order parameters),
which is consistent with our previous U(1) study. However the inclusion of both
the phase and amplitude fluctuations is shown to substantially improve the
qualitative feature of the optical conductivity by showing substantially
reduced Drude peak widths for entire doping range. Both the shift of the hump
position to lower frequency and the growth of the hump peak height with
increasing hole concentration is shown to be consistent with observations.Comment: 7 pages, 6 figure
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