779 research outputs found
Water delivery by pebble accretion to rocky planets in habitable zones in evolving disks
The Earth's ocean mass is only 2.3 x 10^{-4} of the whole planet mass. Even
including water in the interior, it would be at most 10^{-3}-10^{-2}. Ancient
Mars may have had a similar or slightly smaller water fraction. It is important
to clarify the water delivery mechanism to rocky planets in habitable zones in
exoplanetary systems, as well as that to the Earth and Mars. Here, we consider
water delivery to planets by icy pebbles after the snowline inwardly passes the
planetary orbits and derive the water mass fraction (f_{water}) of the final
planet as a function of disk parameters and discuss the parameters that
reproduce f_{water} comparable to that inferred for the Earth and ancient Mars.
We calculate the growth of icy pebbles and their radial drift with a 1D model,
and accretion of icy pebbles onto planets, by simultaneously solving the
snowline migration and the disk dissipation, to evaluate f_{water} of the
planets. We find that f_{water} is regulated by the total mass (M_{res}) of icy
dust materials preserved in the outer disk regions at the timing (t = t_{snow})
of the snowline passage of the planetary orbit. Because M_{res} decays rapidly
after the pebble formation front reaches the disk outer edge (at t = t_{pff}),
f_{water} is sensitive to the ratio t_{snow}/t_{pff}, which is determined by
the disk parameters. We find t_{snow}/t_{pff} 10 is important.
Deriving an analytical formula for f_{water} that reproduces the numerical
results, we find that f_{water} of a rocky planet near 1 au is ~
10^{-4}-10^{-2}, in the disks with initial disk size ~ 30-50 au and the initial
disk mass accretion rate ~ (10^{-8}-10^{-7}) M_sun/y. Because these disks may
be median or slightly compact/massive disks, the water fraction of rocky
planets in habitable zones may be often similar to that of the Earth, if the
icy pebble accretion is responsible for the water delivery.Comment: published in A&A; this is a corrected version from the published
versio
Stock prices and monetary policy in Japan: An analysis of a Bayesian DSGE model
This paper reevaluates the role of asset price stabilization in Japan during the 1980s through a Bayesian estimation of the dynamic stochastic general equilibrium model. Our results show the presence of the wealth channel from increased stock prices in Japan. In addition, we argue the possibility that the Bank of Japan (BOJ) may have conducted its monetary policy by targeting the stock price stability in addition to inflation and the output gap. The BOJ's response to stock price movements as a matter of policy, however, is subject to considerable uncertainty. Our results indicate that while the BOJ may have reacted to stock prices deviated from their fundamental values, it could not prevent a stock price bubble simply by implementing a contractionary monetary policy shock. Therefore, we conclude that the BOJ's monetary policy stance aimed at stabilizing stock price fluctuations and minimizing macroeconomic volatility, whereas endogenous volatility was caused by bad shocks
A note on stock price dynamics and monetary policy in a small open economy
This note examines the role of stock price stabilization in a small open new Keynesian model. We show that stabilizing stock prices is desirable to attain a unique rational expectations equilibrium and that the open economy effect has a significant impact on the determinacy condition
Laparoscopic Gastrectomy for Gastric Cancer with Peritoneal Dissemination after Induction Chemotherapy
Gastric cancer with peritoneal dissemination may be diagnosed as unresectable. More recently, as a result of progress in chemotherapy, some patients with peritoneal dissemination have exhibited extended survival. We report on our experience with three patients in whom induction chemotherapy allowed for totally laparoscopic total gastrectomy (TLTG). All three patients were diagnosed as having advanced gastric cancer with peritoneal dissemination using staging laparoscopy. As induction chemotherapy, S-1 combined with cisplatin was administered to two patients and trastuzumab plus capecitabine combined with cisplatin to one patient. TLTG was performed in all patients and there were no postoperative complications. Adjuvant chemotherapy was initiated within 3 weeks after surgery in all three patients. Laparoscopic gastrectomy undertaken after induction chemotherapy was found to be effective and safe; this treatment has the potential to achieve good treatment outcomes in patients with stage IV gastric cancer
Analysis of multiple compound–protein interactions reveals novel bioactive molecules
The authors use machine learning of compound-protein interactions to explore drug polypharmacology and to efficiently identify bioactive ligands, including novel scaffold-hopping compounds for two pharmaceutically important protein families: G-protein coupled receptors and protein kinases
Long-term efficacy of intravenously administered immunoglobulin in a case of polymyositis with limited application of steroid therapy.
A 72-year-old man who had been diagnosed with polymyositis (PM) was admitted to our hospital for pneumonia with exacerbation of muscle weakness, elevation of muscle enzymes, and positive magnetic resonance imaging findings. The patient had been refractory to cyclosporine A or azathioprine and hoped to avoid administration of high-dose steroids; IV immunoglobulin (IVIG) was therefore administered after improvement of the pneumonia. Two weeks after the IVIG therapy, muscle test scores, activities of daily living, and muscle enzymes were drastically improved. Twenty months after IVIG, no relapse of PM was observed
ALMA High-resolution Multiband Analysis for the Protoplanetary Disk around TW Hya
We present a high-resolution (2.5 au) multiband analysis of the
protoplanetary disk around TW Hya using ALMA long baseline data at Bands 3, 4,
6, and 7. We aim to reconstruct a high-sensitivity millimeter continuum image
and revisit the spectral index distribution. The imaging is performed by
combining new ALMA data at Bands 4 and 6 with available archive data. Two
methods are employed to reconstruct the images; multi-frequency synthesis (MFS)
and the fiducial image-oriented method, where each band is imaged separately
and the frequency dependence is fitted pixel by pixel. We find that the MFS
imaging with the second order of Taylor expansion can reproduce the frequency
dependence of the continuum emission between Bands 3 and 7 in a manner
consistent with previous studies and is a reasonable method to reconstruct the
spectral index map. The image-oriented method provides a spectral index map
consistent with the MFS imaging, but with a two times lower resolution. Mock
observations of an intensity model were conducted to validate the images from
the two methods. We find that the MFS imaging provides a high-resolution
spectral index distribution with an uncertainty of ~\%. Using the
submillimeter spectrum reproduced from our MFS images, we directly calculated
the optical depth, power-law index of the dust opacity coefficient (),
and dust temperature. The derived parameters are consistent with previous
works, and the enhancement of within the intensity gaps is also
confirmed, supporting a deficit of millimeter-sized grains within the gaps.Comment: 17pages, 12 figures, Accepted for publication in The Astrophysical
Journa
Involvement of autophagy in trypsinogen activation within the pancreatic acinar cells
Autophagy is mostly a nonselective bulk degradation system within cells. Recent reports indicate that autophagy can act both as a protector and killer of the cell depending on the stage of the disease or the surrounding cellular environment (for review see Cuervo, A.M. 2004. Trends Cell Biol. 14:70–77). We found that cytoplasmic vacuoles induced in pancreatic acinar cells by experimental pancreatitis were autophagic in origin, as demonstrated by microtubule-associated protein 1 light chain 3 expression and electron microscopy experiments. To analyze the role of macroautophagy in acute pancreatitis, we produced conditional knockout mice lacking the autophagy-related 5 gene in acinar cells. Acute pancreatitis was not observed, except for very mild edema in a restricted area, in conditional knockout mice. Unexpectedly, trypsinogen activation was greatly reduced in the absence of autophagy. These results suggest that autophagy exerts devastating effects in pancreatic acinar cells by activation of trypsinogen to trypsin in the early stage of acute pancreatitis through delivering trypsinogen to the lysosome
External RMP effect on locked-mode-like instability in helical plasmas
The slowing-down mechanism of the locked-mode-like instabilities with and without an island structure is investigated through the effects of an external RMP (resonant magnetic perturbation) on the instabilities. For both instabilities, the slowing-down duration decreases with the increase in the external RMP, and the RMP dependence is consistent with the braking model of the j × B force due to the interaction between the instabilities and the external RMP. Moreover, the relationship between the amplitude and the frequency of both locked-mode-like instabilities during the slowing down is consistent with the force balance model between the j × B force due to the external RMP and a viscous force. These results suggest that the slowing down of both locked-mode-like instabilities with finite external RMP occurs due to the j × B force driven by the external RMP
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