1,555 research outputs found
Particle-Swarm-Optimization-Based Selective Neural Network Ensemble and Its Application to Modeling Resonant Frequency of Microstrip Antenna
Synergistic Effects between Phosphorylation of Phospholamban and Troponin I Promote Relaxation at Higher Heart Rate
We hypothesized that the extent of frequency-dependent acceleration of relaxation (FDAR) would be less than that of isoproterenol-(ISO-)dependent acceleration of relaxation (IDAR) at the same increment of heart rates, and ISO may improve FDAR. Cardiac function and phosphorylation of PLB and cTnI were compared in pacing, ISO treatment, and combined pacing and ISO treatment in isolated working heart. The increase in cardiac output and the degree of relaxation was less in pacing than in ISO treatment at the same increment of heart rates. The increasing stimulation frequency induced more significant relaxant effect in ISO perfusion than that in physiological salt perfusion. The pacing only phosphorylated PLB at Thr17, but ISO induced phosphorylation of cTnI and PLB at Ser16 and Thr17. Those results suggest that the synergistic effects of PLB and cTnI induce higher degree of relaxation which makes a sufficient diastolic filling of the ventricle at higher heart rate
One Fits All: A Unified Synchrotron Model Explains GRBs with FRED-Shaped Pulses
The analysis of gamma-ray burst (GRB) spectra often relies on empirical
models like the Band function, which lacks a distinct physical explanation.
Previous attempts to couple physical models with observed data have been
confined to individual burst studies, where the model is fitted to segmented
spectra with independent physical parameters. These approaches frequently fail
to explain the spectral evolution, which should be governed by a consistent set
of physical conditions. In this study, we propose a novel approach by
incorporating the synchrotron radiation model to provide a self-consistent
explanation for a selection of single-pulse GRBs. Our sample is carefully
chosen to minimize contamination from overlapping pulses, allowing for a
comprehensive test of the synchrotron model under a unified physical condition,
such as a single injection event of electrons. By tracing the evolution of
cooling electrons in a decaying magnetic field, our model predicts a series of
time-dependent observed spectra that align well with the observed data.
Remarkably, using a single set of physical parameters, our model successfully
fits all time-resolved spectra within each burst. Additionally, our model
accurately predicts the evolution of some key features of GRBs such as the
spectral peak and light curve shapes, all of which are consistent
with observations. Our findings strongly support the notion that the spectral
and temporal evolution in GRB pulses originates from the expansion of the GRB
emission region with an initial radius of approximately cm, with
synchrotron radiation being the underlying emission mechanism.Comment: 25 pages, 18 figures, 4 table
MSGCorep: A package for corepresentations of magnetic space groups
Motivated by easy access to complete corepresentation (corep) data of all the
1651 magnetic space groups (MSGs) in three-dimensional space, we have developed
a Mathematica package MSGCorep to provide an offline database of coreps and
various functions to manipulate them, based on our previous package
SpaceGroupIrep. One can use the package MSGCorep to obtain the elements of any
MSG and magnetic little group, to calculate the multiplication of group
elements, to obtain the small coreps at any k-point and full coreps of any
magnetic k-star for any MSG and show them in a user-friendly table form, to
calculate and show the decomposition of direct products of full coreps between
any two specified magnetic k-stars, and to determine the small coreps of energy
bands. Both single-valued and double-valued coreps are supported. In addition,
the 122 magnetic point groups (MPGs) and their coreps are also supported by
this package. To the best of our knowledge, MSGCorep is the first package that
is able to calculate the direct product of full coreps for any MSG and able to
determine small coreps of energy bands for general purpose. In a word, the
MSGCorep package is an offline database and tool set for MSGs, MPGs, and their
coreps, and it is very useful to study the symmetries in magnetic and
nonmagnetic materials.Comment: 23 pages, 7 figures, 6 tables, 1 supplementary materia
The strong vertices of bottom mesons , and bottomonia ,
In this article, the strong coupling constants of vertices ,
, , and
are analyzed in the framework of QCD sum rules. In this
work, all possible off-shell cases and the contributions of vacuum condensate
terms including , , , and
are considered. The
momentum dependent strong coupling constants are first calculated and then are
fitted into analytical functions which are used to extrapolate into
time-like regions to obtain the final values of strong coupling constants. The
final results are ,
GeV,
,
and
GeV. These strong
coupling constants are important input parameters which reflect the dynamic
properties of the interactions among the mesons and quarkonia
Analysis of the strong vertices of and in QCD sum rules
In this work, we analyze the strong vertices and
using the three-point QCD sum rules under the tensor
structures ,
and . We firstly calculate the momentum
dependent strong coupling constants by considering contributions of
the perturbative part and the condensate terms ,
, and
. By fitting these coupling constants into
analytical functions and extrapolating them into time-like regions, we then
obtain the on-shell values of strong coupling constants for these vertices. The
results are GeV,
GeV,
GeV,
GeV,
GeV and
GeV. These strong
coupling constants are important parameters which can help us to understand the
strong decay behaviors of hadrons
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