796 research outputs found
Poly-instanton axion inflation
We investigate the axion inflation model derived by poly-instanton effects in
type II superstring theories. Poly-instanton effects are instanton effects
corrected by another instanton and it can generate the modulus-axion potential
with the double exponential function. Although the axion has a period of small
value, this potential can have a flat region because its derivatives are
exponentially suppressed by non-perturbative effects. From the view point of
the cosmic inflation, such potential is interesting. In this paper, we
numerically study the possibilities for realizing the cosmic inflation. We also
study their spectral index and other cosmological observables, numerically.Comment: 13 pages, 2 figure
Experimental variable effects on laser heating of inclusions during Raman spectroscopic analysis
Raman spectroscopy for fluid, melt, and mineral inclusions provides direct insight into the physicochemical conditions of the environment surrounding the host mineral at the time of trapping. However, the obtained Raman spectral characteristics such as peak position are modified because of local temperature enhancement of the inclusions by the excitation laser, which might engender systematic errors and incorrect conclusions if the effect is not corrected. Despite the potentially non-negligible effects of laser heating, the laser heating coefficient (B) (°C/mW) of inclusions has remained unsolved. For this study, we found B from experiments and heat transport simulation to evaluate how various parameters such as experimental conditions, mineral properties, and inclusion geometry affect B of inclusions. To assess the parameters influencing laser heating, we measured B of a total of 19 CO2-rich fluid inclusions hosted in olivine, orthopyroxene, clinopyroxene, spinel, and quartz. Our results revealed that the measured B of fluid inclusions in spinel is highest (approx. 6 °C/mW) and that of quartz is lowest (approx. 1 × 10−2 °C/mW), consistent with earlier inferences. Our simulation results show that the absorption coefficient of the host mineral is correlated linearly with B. It is the most influential parameter when the absorption coefficient of the host mineral (αh) is larger than that of an inclusion (αinc). Furthermore, although our results indicate that both the inclusion size and depth have little effect on B if αh > αinc, the thickness and radius of the host mineral slightly influence B. These results suggest that the choice of inclusion size and depth to be analyzed in a given sample do not cause any systematic error in the Raman data because of laser heating, but the host radius and thickness, which can be adjusted to some degree at the time of sample preparation, can cause systematic errors between samples.Our results demonstrate that, even with laser power of 10 mW, which is typical for inclusion analysis, the inclusion temperature rises to tens or hundreds of degrees during the analysis, depending especially on the host mineral geometry and optical properties. Therefore, correction of the heating effects will be necessary to obtain reliable data from Raman spectroscopic analysis of inclusions. This paper presents some correction methods for non-negligible effects of laser heating
F-term Moduli Stabilization and Uplifting
We study K\"ahler moduli stabilization in IIB superstring theory. We propose
a new moduli stabilization mechanism by the supersymmetry-braking chiral
superfield which is coupled to K\"ahler moduli in K\"ahler potential. We also
study uplifting of the Large Volume Scenario (LVS) by it. In both cases, the
form of superpotential is crucial for moduli stabilization. We confirm that our
uplifting mechanism does not destabilize the vacuum of the LVS drastically.Comment: 22 pages, 2 figure
Effect of Age on the Changes of Pitlsitary and Serum Gonadotrophin Levels during PMS-Induced Ovulation in Prepubertal Rats
Development of Pancreatic Ductal Adenocarcinoma Associated with Intraductal Papillary Mucinous Neoplasia
We retrospectively investigated the incidence of pancreatic ductal adenocarcinoma among patients with intraductal papillary mucinous neoplasms of the pancreas. Based on imaging in 195 such patients, we chose surgery as initial treatment for 54, and periodic evaluation over 6 to 192 months (mean, 52) for 141. In 6 of the 141 patients observed for intraductal papillary mucinous neoplasm (4.2%), pancreatic ductal adenocarcinoma developed. Further, careful monitoring for cancer occurrence in the remnant pancreas proved essential in the surgical resection group; 2 of 26 patients (7.7%) subsequently developed pancreatic ductal adenocarcinoma in the remnant pancreas, at 41 months and 137 months after surgery. Serial observation of patients with intraductal papillary mucinous neoplasms by contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography therefore is critical, whether or not surgical treatment initially was performed
Measurement of Leakage Neutron Spectra from a Spherical Pile of Niobium Bombarded with 14 MeV Neutrons and Validation of Its Nuclear Data.
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