205 research outputs found
Monte Carlo study of particle production in diffractive proton-proton collisions at = 13 TeV with the very forward detector combined with central information
Very forward (VF) detectors in hadron colliders, having unique sensitivity to
diffractive processes, can be a powerful tool for studying diffractive
dissociation by combining them with central detectors. Several Monte Carlo
simulation samples in - collisions at TeV were analyzed,
and different nondiffractive and diffractive contributions were clarified
through differential cross sections of forward neutral particles. Diffraction
selection criteria in the VF-triggered-event samples were determined by using
the central track information. The corresponding selection applicable in real
experiments has 100% purity and 30%-70% efficiency. Consequently, the
central information enables classification of the forward productions into
diffraction and nondiffraction categories; in particular, most of the surviving
events from the selection belong to low-mass diffraction events at
. Therefore, the combined method can uniquely access
the low-mass diffraction regime experimentally.Comment: 10 pages, 16 figures, 1table
Physical Relation of Source I to IRc2 in the Orion KL Region
We present mid-infrared narrow-band images of the Orion BN/KL region, and
N-band low-resolution spectra of IRc2 and the nearby radio source "I." The
distributions of the silicate absorption strength and the color temperature
have been revealed with a sub-arcsecond resolution. The detailed structure of
the 7.8 micron/12.4 micron color temperature distribution was resolved in the
vicinity of IRc2. A mid-infrared counterpart to source I has been detected as a
large color temperature peak. The color temperature distribution shows an
increasing gradient from IRc2 toward source I, and no dominant temperature peak
is seen at IRc2. The spectral energy distribution of IRc2 could be fitted by a
two-temperature component model, and the "warmer component" of the infrared
emission from IRc2 could be reproduced by scattering of radiation from source
I. IRc2 itself is not self-luminous, but is illuminated and heated by an
embedded luminous young stellar object located at source I.Comment: 20 pages, 11 figures. Minor corrections had been done in the ver.2.
Accepted for publication in PAS
Effects of galactic magnetic field on the UHECR correlation studies with starburst galaxies
We estimate the biases caused by the coherent deflection of cosmic rays due
to the Galactic magnetic field (GMF) in maximum-likelihood analysis for
searches of ultrahigh-energy cosmic ray (UHECR) sources in the literature. We
simulate mock event datasets with a set of assumptions for the starburst galaxy
(SBG) source model (arXiv:1801.06160), coherent deflection by a GMF model
(arXiv:1204.3662,arXiv:1210.7820), and mixed-mass composition
(arXiv:1901.03338); we then conduct a maximum-likelihood analysis without
accounting for the GMF in the same manner as previous studies. We find that the
anisotropic fraction is estimated systematically lower than the
true value. We estimate the true parameters which are compatible with the
best-fit parameters reported in (arXiv:1801.06160), and find that except for a
narrow region with a large anisotropic fraction and small separation angular
scale a wide parameter space is still compatible with the experimental results.
We also develop a maximum-likelihood method that takes into account the GMF
model and confirm in the MC simulations that we can estimate the true
parameters within a 1 contour under the ideal condition that we know
the event-by-event mass and the GMF
Origin of diverse phosphorylation patterns in the ERBB system
シグナル伝達による多様な細胞応答の起源 --実験と理論の融合による反応特性の決定. 京都大学プレスリリース. 2022-01-21.Intercellular signals induce various cellular responses, including growth, proliferation, and differentiation, via the dynamic processes of signal transduction pathways. For cell fate decisions, ligand-binding induces the phosphorylation of ERBB receptors, which in turn activate downstream molecules. The ERBB family includes four subtypes, which diverged through two gene duplications from a common ancestor. Differences in the expression patterns of the subtypes have been reported between different organs in the human body. However, how these different expression properties influence the diverse phosphorylation levels of ERBB proteins is not well understood. Here we study the origin of the phosphorylation responses by experimental and mathematical analyses. The experimental measurements clarified that the phosphorylation levels heavily depend on the ERBB expression profiles. We developed a mathematical model consisting of the four subtypes as monomers, homodimers, and heterodimers and estimated the rate constants governing the phosphorylation responses from the experimental data. To understand the origin of the diversity, we analyzed the effects of the expression levels and reaction rates of the ERBB subtypes on the diversity. The difference in phosphorylation rates between ERBB subtypes showed a much greater contribution to the diversity than did the dimerization rates. This result implies that divergent evolution in phosphorylation reactions rather than in dimerization reactions after whole genome duplications was essential for increasing the diversity of the phosphorylation responses
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