131 research outputs found
Non-Smooth Stochastic Lyapunov Functions With Weak Extension of Viscosity Solutions
This paper proposes a notion of viscosity weak supersolutions to build a
bridge between stochastic Lyapunov stability theory and viscosity solution
theory. Different from ordinary differential equations, stochastic differential
equations can have the origins being stable despite having no smooth stochastic
Lyapunov functions (SLFs). The feature naturally requires that the related
Lyapunov equations are illustrated via viscosity solution theory, which deals
with non-smooth solutions to partial differential equations. This paper claims
that stochastic Lyapunov stability theory needs a weak extension of viscosity
supersolutions, and the proposed viscosity weak supersolutions describe
non-smooth SLFs ensuring a large class of the origins being noisily
(asymptotically) stable and (asymptotically) stable in probability. The
contribution of the non-smooth SLFs are confirmed by a few examples;
especially, they ensure that all the linear-quadratic-Gaussian (LQG) controlled
systems have the origins being noisily asymptotically stable for any additive
noises
Mass Ejection from the Remnant of a Binary Neutron Star Merger: Viscous-Radiation Hydrodynamics Study
We perform long-term general relativistic neutrino radiation hydrodynamics
simulations (in axisymmetry) for a massive neutron star (MNS) surrounded by a
torus, which is a canonical remnant formed after the binary neutron star
merger. We take into account the effects of viscosity, which is likely to arise
in the merger remnant due to magnetohydrodynamical turbulence. As the initial
condition, we employ the azimuthally averaged data of the MNS-torus system
derived in a three-dimensional, numerical-relativity simulation for the binary
neutron star merger. The viscous effect plays key roles for the remnant
evolution and mass ejection from it in two phases of the evolution. In the
first ms, a differential rotation state of the MNS is changed to
a rigidly rotating state, and as a result, a sound wave, which subsequently
becomes a shock wave, is formed in the vicinity of the MNS due to the variation
of the quasi-equilibrium state of the MNS. The shock wave induces significant
mass ejection of mass for the alpha
viscosity parameter of . For the longer-term evolution with s, a significant fraction of the torus material is ejected. The ejecta
mass is likely to be of order , so that the total mass of the
viscosity-driven ejecta could dominate that of the dynamical ejecta of mass
. The electron fraction, , of the ejecta is
always high enough () that this post-merger ejecta is
lanthanide-poor; hence, the opacity of the ejecta is likely to be
times lower than that of the dynamical ejecta. This indicates that the
electromagnetic signal from the ejecta would be rapidly evolving, bright, and
blue if it is observed from a small viewing angle () for
which the effect of the dynamical ejecta is minor.Comment: 21 pages, 18 figures, accepted for publication in Ap
Production of all the r-process nuclides in the dynamical ejecta of neutron star mergers
Recent studies suggest that binary neutron star (NS-NS) mergers robustly
produce the heavy r-process nuclei above the atomic mass number A ~ 130 because
of their ejecta consisting of almost pure neutrons (electron fraction of Y_e <
0.1). However, little production of the lighter r-process nuclei (A = 90-120)
conflicts with the spectroscopic results of r-process-enhanced Galactic halo
stars. We present, for the first time, the result of nucleosynthesis
calculations based on the fully general-relativistic simulation of a NS-NS
merger with approximate neutrino transport. It is found that the bulk of the
dynamical ejecta are appreciably shock-heated and neutrino-processed, resulting
in a wide range of Y_e (= 0.09-0.45). The mass-averaged abundance distribution
of calculated nucleosynthesis yields is in reasonable agreement with the
full-mass range (A = 90-240) of the solar r-process curve. This implies, if our
model is representative of such events, that the dynamical ejecta of NS-NS
mergers can be the origin of the Galactic r-process nuclei. Our result also
shows that the radioactive heating after ~ 1 day from the merging, giving rise
to r-process-powered transient emission, is dominated by the beta-decays of
several species close to stability with precisely measured half-lives. This
implies that the total radioactive heating rate for such an event can be well
constrained within about a factor of two if the ejected material has a
solar-like r-process pattern.Comment: 6 pages, 5 figures, accepted for publication in ApJL. Section 2 was
significantly changed according to the referee's advices. Our result was
unchange
Identification of the chromosomal region responsible for high-temperature stress tolerance during the grain-filling period in rice
Usefulness of the Multimodal Fusion Image for Visualization of Deep Sylvian Veins
The preoperative assessment of cerebral veins is important to avoid unexpected cerebral venous infarction
in the neurosurgical setting. However, information is particularly limited regarding deep
Sylvian veins, which occasionally disturb surgical procedures for cerebral anterior circulation aneurysms.
The predictability of detecting deep Sylvian veins and their tributaries using a modern multimodal
fusion image was aimed to be evaluated. Moreover, 51 patients who underwent microsurgery
for unruptured cerebral aneurysms with Sylvian fissure dissection were retrospectively reviewed. The
visualization of the four components of the deep Sylvian veins in conventional computed tomography
(CT) venography and multimodal fusion images was evaluated. To compare the detection accuracy
among these radiological images, the sensitivity and specificity for the detection of each of the four
venous structures were calculated in comparison with those of intraoperative inspections. The kappa
coefficients were also measured and the inter-rater agreement for each venous structure in each radiological
image was examined. In all veins, the multimodal fusion image exhibited a high detection
rate without statistical difference from intraoperative inspections (P = 1.0). However, CT venography
exhibited a low detection rate with a significant difference from intraoperative inspections in the
common vertical trunk (P = 0.006) and attached vein (P = 0.008). The kappa coefficients of the fusion
image ranged from 0.73 to 0.91 and were superior to those of CT venography for all venous structures.
This is the first report to indicate the usefulness of a multimodal fusion image in evaluating deep
Sylvian veins, especially for the detection of nontypical, relatively small veins with large individual
variability.博士(医学)・甲第864号・令和5年3月15
Titanium peroxide nanoparticles enhanced cytotoxic effects of X-ray irradiation against pancreatic cancer model through reactive oxygen species generation in vitro and in vivo
Details of the synthetic protocol for PAA-TiOxNPs formation from TiO2NPs. (PPTX 151Â kb
The Dugesia ryukyuensis Database as a Molecular Resource for Studying Switching of the Reproductive System
The planarian Dugesia ryukyuensis reproduces both asexually and sexually, and can switch from one mode of reproduction to the other. We recently developed a method for experimentally switching reproduction of the planarian from the asexual to the sexual mode. We constructed a cDNA library from sexualized D. ryukyuensis and sequenced and analyzed 8,988 expressed sequence tags (ESTs). The ESTs were analyzed and grouped into 3,077 non-redundant sequences, leaving 1,929 singletons that formed the basis of unigene sets. Fifty-six percent of the cDNAs analyzed shared similarity (E-value<1E -20) with sequences deposited in NCBI. Highly redundant sequences encoded granulin and actin, which are expressed in the whole body, and other redundant sequences encoded a Vasa-like protein, which is known to be a component of germ-line cells and is expressed in the ovary, and Y-protein, which is expressed in the testis. The sexualized planarian expressed sequence tag database (http://planaria.bio.keio.ac.jp/planaria/) is an open-access, online resource providing access to sequence, classification, clustering, and annotation data. This database should constitute a powerful tool for analyzing sexualization in planarians
非機能性下垂体腺腫における経鼻内視鏡下経蝶形骨洞手術後の遅発性低ナトリウム血症の手術因子の検討
Purpose Delayed hyponatremia can occur after pituitary surgery, resulting in prolonged hospitalization. However, the
influence of surgical factors after such a procedure has not been well established. The impact of surgery and related factors
on delayed hyponatremia was investigated.
Methods This was a retrospective analysis of 137 consecutive patients who underwent transsphenoidal surgery for a
nonfunctioning pituitary adenoma between 2008 and 2019. Preoperative (demographics, comorbidities), intraoperative
(resection extent, operation time, blood loss volume, cerebrospinal fluid leak, tumor consistency), and postoperative
[hematoma, meningitis, diabetes insipidus (DI), hormonal assessment] data were collected, with statistical analysis of each
factor performed.
Results Among the 137 patients, delayed hyponatremia occurred in 31 (22.6%). Multivariate analysis revealed that those
with hypertension had a significantly higher likelihood of avoiding delayed hyponatremia (p = 0.004). Although no correlations
of direct surgical factors with delayed hyponatremia were found, multivariate analysis of indirect surgical factors
showed that presence of a firm tumor, transient DI, and meningitis were significantly associated with delayed hyponatremia
(p = 0.014, 0.001, and 0.047, respectively). There was also a significant association of severe hyponatremia with appearance
of symptoms (p = 0.002).
Conclusion There was a tendency for hypertension to be associated with delayed hyponatremia avoidance, with indirect
surgical factors including tumor consistency, transient DI, and meningitis found to have an influence on delayed hyponatremia.
It was concluded that attention should be given to non-hypertensive patients with a firm tumor, transient DI, or
meningitis after pituitary surgery, as delayed hyponatremia may occur.博士(医学)・甲第871号・令和5年3月15
Stomatal regulators are co-opted for seta development in the astomatous liverwort Marchantia polymorpha
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