1,169 research outputs found
Heavy-to-light form factors in the quark model with heavy propagators
We calculate the heavy-to-light form factors in the relativistic quark model
with heavy infrapropagators. Their q^2-dependence in the physical region is
defined by two parameters: the "infrared" parameter \nu characterizing the
infrared behavior of the heavy quark and the mass difference of the heavy meson
and heavy quark E=m_H-M_Q. It is found that the values of the D\to K(K^*) and
D\to \pi(\rho) form factors at q^2=0 are in excellent agreement with the
available experimental data and other approaches whereas these values for B\to
\pi(\rho) transitions are found to be larger than those of several other
models. The obtained form factors are used to calculate the widths of the
semileptonic decays of B and D mesons. The comparison of our results with the
available experimental data and other approaches is givenComment: 15 pages, 3 eps figures. New references are added, corrected some
typos. To appear in Few-Body System
Visualization of internal structure and internal stress in visibly opaque objects using full-field phase-shifting terahertz digital holography
We construct a full-field phase-shifting terahertz digital holography (PS-THz-DH) system by use of a THz quantum cascade laser and an uncooled, 2D micro-bolometer array. The PS-THz-DH enables us to separate the necessary diffraction-order image from unnecessary diffraction-order images without the need for spatial Fourier filtering, leading to suppress the decrease of spatial resolution. 3D shape of a visibly opaque object is visualized with a sub-millimeter lateral resolution and a sub-μm axial resolution. Also, the digital focusing of amplitude image enables the visualization of internal structure with the millimeter-order axial selectivity. Furthermore, the internal stress distribution of an externally compressed object is visualized from the phase image. The demonstrated results imply a possibility for non-destructive inspection of visibly opaque non-metal materials
Spin observables of the reactions NN -> DeltaN and pd -> Delta (pp)(1S0) in collinear kinematics
A general formalism for double and triple spin-correlations of the reaction
NN -> DeltaN is developed for the case of collinear kinematics. A complete
polarization experiment allowing to reconstruct all of the four amplitudes
describing this process is suggested. Furthermore, the spin observables of the
inelastic charge-exchange reaction pd -> Delta^0(pp)(1S0) are analyzed in
collinear kinematics within the single pN scattering mechanism involving the
subprocess pn -> Delta^0p. The full set of spin observables related to the
polarization of one or two initial particles and one final particle is obtained
in terms of three invariant amplitudes of the reaction pd -> Delta (pp)(1S0)
and the transition form factor d->(pp)(1S0). A complete polarization experiment
for the reaction pd -> Delta^0(pp)(1S0) is suggested which allows one to
determine three independent combinations of the four amplitudes of the
elementary subprocess NN -> DeltaN.Comment: 12 pages, 1 figur
Characterization of a genetic and antigenic variant of avian paramyxovirus 6 isolated from a migratory wild bird, the red-necked stint (Calidris ruficollis)
A hemagglutinating virus (8KS0813) was isolated from a red-necked stint. Hemagglutination inhibition and neutralization tests indicated that 8KS0813 was antigenically related to a prototype strain, APMV-6/duck/Hong Kong/18/199/77, but with an 8- and 16-fold difference, respectively, in their titers. The full genome sequence of 8KS0813 showed 98.6 % nucleotide sequence identity to that of APMV-6/duck/Italy/4524-2/07, which has been reported to belong to an APMV-6 subgroup, and showed less similarity to that of the prototype strain (70.6 % similarity). The growth of 8KS0813 and the prototype strain in four different cell cultures was greatly enhanced by adding trypsin. Interestingly, this virus induced syncytia only in Vero cells. 8KS0813 was identified as APMV-6/red-necked stint/Japan/8KS0813/08, but it is antigenically and genetically distinguishable from the prototype strain, suggesting that variant APMV-6 is circulating in migratory birds.Program of Founding Research Centers for Emerging and Reemerging Infectious DiseasesJapan. Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Exploratory Research (19659115))National Institute of Allergy and Infectious Diseases (U.S.) (NIAID contracts HHSN266200700009C and HHSN266200700007C
Future-proofing geotechnics workflows: accelerating problem-solving with large language models
The integration of Large Language Models (LLMs) like ChatGPT into the
workflows of geotechnical engineering has a high potential to transform how the
discipline approaches problem-solving and decision-making. This paper delves
into the innovative application of LLMs in geotechnical engineering, as
explored in a hands-on workshop held in Tokyo, Japan. The event brought
together a diverse group of 20 participants, including students, researchers,
and professionals from academia, industry, and government sectors, to
investigate practical uses of LLMs in addressing specific geotechnical
challenges. The workshop facilitated the creation of solutions for four
different practical geotechnical problems as illustrative examples, culminating
in the development of an academic paper. The paper discusses the potential of
LLMs to transform geotechnical engineering practices, highlighting their
proficiency in handling a range of tasks from basic data analysis to complex,
multimodal problem-solving. It also addresses the challenges in implementing
LLMs, particularly in achieving high precision and accuracy in specialized
tasks, and underscores the need for expert oversight. The findings demonstrate
LLMs' effectiveness in enhancing efficiency, data processing, and
decision-making in geotechnical engineering, suggesting a paradigm shift
towards more integrated, data-driven approaches in this field. This study not
only showcases the potential of LLMs in a specific engineering domain, but also
sets a precedent for their broader application in interdisciplinary research
and practice, where the synergy of human expertise and artificial intelligence
redefines the boundaries of problem-solving.Comment: Supplementary information will be available upon reques
On the thermoelectricity of correlated electrons in the zero-temperature limit
The Seebeck coefficient of a metal is expected to display a linear
temperature-dependence in the zero-temperature limit. To attain this regime, it
is often necessary to cool the system well below 1K. We put under scrutiny the
magnitude of this term in different families of strongly-interacting electronic
systems. For a wide range of compounds (including heavy-fermion, organic and
various oxide families) a remarkable correlation between this term and the
electronic specific heat is found. We argue that a dimensionless ratio relating
these two signatures of mass renormalisation contains interesting information
about the ground state of each system. The absolute value of this ratio remains
close to unity in a wide range of strongly-correlated electron systems.Comment: 15 pages, including two figure
Clinical meaning of sarcopenia in patients undergoing endoscopic treatment
With increasing global life expectancy, the significance of geriatric assessment parameters has increased. Sarcopenia is a crucial assessment parameter and is defined as the age-related loss of muscle mass and strength. Sarcopenia is widely acknowledged as a risk factor for postoperative complications in diverse advanced malignancies and has a detrimental effect on the long-term prognosis. While most studies have primarily concentrated on the correlation between sarcopenia and advanced cancer, more recent investigations have focused on the relationship between sarcopenia and early-stage cancer. Endoscopic submucosal dissection (ESD), which is less invasive than surgical intervention, is extensively employed in the management of early-stage cancer, although it is associated with complications such as bleeding and perforation. In recent years, several reports have revealed the adverse consequences of sarcopenia in patients with early-stage cancer undergoing ESD. This literature review briefly summarizes the recent studies on the association between sarcopenia and ESD
Detection of Multi-TeV Gamma Rays from Markarian 501 during an Unforeseen Flaring State in 1997 with the Tibet Air Shower Array
In 1997, the BL Lac Object Mrk 501 entered a very active phase and was the
brightest source in the sky at TeV energies, showing strong and frequent
flaring. Using the data obtained with a high density air shower array that has
been operating successfully at Yangbajing in Tibet since 1996, we searched for
gamma-ray signals from this source during the period from February through
August in 1997. Our observation detected multi-TeV -ray signals at the
3.7-Sigma level during this period. The most rapid increase of the excess
counts was observed between April 7 and June 16 and the statistical
significance of the excess counts in this period was 4.7-Sigma. Among several
observations of flaring TeV gamma-rays from Mrk 501 in 1997, this is the only
observation using a conventional air shower array. We present the energy
spectrum of gamma-rays which will be worthy to compare with those obtained by
imaging atmospheric Cerenkov telescopes.Comment: 9 pages, 7 figures, To appear in Ap
Observation of Multi-Tev Gamma Rays from the Crab Nebula Using the Tibet Air Shower Array
The Tibet experiment, operating at Yangbajing (4,300 m above sea level), is
the lowest energy air shower array and the new high density array constructed
in 1996 has sensitivity to -ray air showers at energies as low as 3
TeV. With this new array, the Crab Nebula was observed in multi-TeV
-rays and a signal was detected at the 5.5 level. We also
obtained the energy spectrum of -rays in the energy region above 3 TeV
which partially overlaps those observed with imaging atmospheric Cherenkov
telescopes. This is the first observation of -ray signals from point
sources with a conventional air shower array using scintillation detectors.Comment: 9 pages, 4 figures, Accepted for publication in ApJ Letter
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