4,588 research outputs found
Constraints on the mass of a habitable planet with water of nebular origin
From an astrobiological point of view, special attention has been paid to the
probability of habitable planets in extrasolar systems. The purpose of this
study is to constrain a possible range of the mass of a terrestrial planet that
can get water. We focus on the process of water production through oxidation of
the atmospheric hydrogen--the nebular gas having been attracted
gravitationally--by oxide available at the planetary surface. For the water
production to work well on a planet, a sufficient amount of hydrogen and enough
high temperature to melt the planetary surface are needed. We have simulated
the structure of the atmosphere that connects with the protoplanetary nebula
for wide ranges of heat flux, opacity, and density of the nebular gas. We have
found both requirements are fulfilled for an Earth-mass planet for wide ranges
of the parameters. We have also found the surface temperature of planets of <=
0.3 Earth masses is lower than the melting temperature of silicate (~ 1500K).
On the other hand, a planet of more than several Earth masses becomes a gas
giant planet through runaway accretion of the nebular gas.Comment: 25 pages, 8 figures, to appear in the 01 September 2006 issue of Ap
The interaction of amyloid A beta(1-40) with lipid bilayers and ganglioside as studied by P-31 solid-state NMR
Amyloid P-peptide (A beta) is a major component of plaques in Alzheimer's disease, and formation of senile plaques has been suggested to originate fro m regions of neuronal membrane rich in gangliosides. We analyzed the mode of interaction of A beta with lipid bilayers by multinuclear NMR using P-31 nuclei. We found that A beta (1-40) strongly perturbed the bilayer structure of dimyristoylphosphatidylcholine (DMPQ, to form a non-lamellar phase (most likely micellar). The ganglioside GM1 potentiated the effect of A beta (1-40), as viewed from P-31 NMR. The difference of the isotropic peak intensity between DMPC/A beta and DMPC/GM1/A beta suggests a specific interaction between A beta and GM1. We show that in the DMPC/GM1/A beta system there are three lipid phases, namely a lamellar phase, a hexagonal phase and non-oriented lipids. The latter two phases are induced by the presence of the A beta peptide, and facilitated by GM1. 9) 2008 Elsevier Ireland Ltd. All rights reserved
Lateness Gene Concerning Photosensitivity Increases Yield, by Applying Low to High Levels of Fertilization, in Rice, a Preliminary Report
Various genes controlling heading time have been reported in rice. An isogenic-line pair of late and early lines “L” and “E” were developed from progenies of the F1 of Suweon 258 × an isogenic line of IR36 carrying Ur1 gene. The lateness gene for photosensitivity that causes the difference between L and E was tentatively designated as “Ex(t)”, although it's chromosomal location is unknown. The present study was conducted to examine the effects of Ex(t) on yield and related traits in a paddy field in two years. Chemical fertilizers containing N, P2O5 and K2O were applied at the nitrogen levels of 4.00, 9.00 and 18.00 g/m2 in total, being denoted by "N4", "N9" and "N18", respectively, in 2014. L was later in 80%-heading by 18 or 19 days than E. Regarding total brown rice yield (g/m2), L and E were 635 and 577, 606 and 548, and 590 and 501, respectively, at N18, N9 and N4, indicating that Ex(t) increased this trait by 10 to 18%. Ex(t) increased yield of brown rice with thickness above 1.5mm (g/m2), by 9 to 15%. Ex(t) increased spikelet number per panicle by 16 to 22% and spikelet number per m2 by 11 to 18%. Thousand-grain weight (g) was 2 to 4% lower in L than in E. L was not significantly different from E in ripened-grain percentage. Hence, Ex(t) increased yield by increasing spikelet number per panicle. It is suggested that Ex(t) could be utilized to develop high yielding varieties for warmer districts of the temperate zone
Neutrophilic dermatoses with acute myeloid leukemia associated with an increase of serum colony-stimulating factor
ArticleJOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY. 59(2)S10-S12(2008)journal articl
Development of Uniform CdTe Pixel Detectors Based on Caltech ASIC
We have developed a large CdTe pixel detector with dimensions of 23.7 x 13.0
mm and a pixel size of 448 x 448 um^2. The detector is based on recent
technologies of an uniform CdTe single crystal, a two-dimensional ASIC, and
stud bump-bonding to connect pixel electrodes on the CdTe surface to the ASIC.
Good spectra are obtained from 1051 pixels out of total 1056 pixels. When we
operate the detector at -50 C, the energy resolution is 0.67 keV and 0.99 keV
at 14 keV and 60 keV, respectively. Week-long stability of the detector is
confirmed at operating temperatures of both -50 C and -20 C. The detector also
shows high uniformity: the peak positions for all pixels agree to within 0.82%,
and the average of the energy resolution is 1.04 keV at a temperature of -50 C.
When we normalized the peak area by the total counts detected by each pixel, a
variation of 2.1 % is obtained.Comment: 11pages, 17figures, accepted for publication in Proc. SPIE 200
Significance of chemokine receptor expression in aggressive NK cell leukemia
ArticleLEUKEMIA. 19(7): 1169-1174 (2005)journal articl
A simple measure of memory for dynamical processes described by the generalized Langevin equation
Memory effects are a key feature in the description of the dynamical systems
governed by the generalized Langevin equation, which presents an exact
reformulation of the equation of motion. A simple measure for the estimation of
memory effects is introduced within the framework of this description.
Numerical calculations of the suggested measure and the analysis of memory
effects are also applied for various model physical systems as well as for the
phenomena of ``long time tails'' and anomalous diffusion
Observation of an energetic radiation burst from mountain-top thunderclouds
During thunderstorms on 2008 September 20, a simultaneous detection of gamma
rays and electrons was made at a mountain observatory in Japan located 2770 m
above sea level. Both emissions, lasting 90 seconds, were associated with
thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV,
can be interpreted as consisting of bremsstrahlung gamma rays arriving from a
source which is 60 - 130 m in distance at 90% confidence level. The observed
electrons are likely to be dominated by a primary population escaping from an
acceleration region in the clouds.Comment: 12 pages, 3 figures, accepted for publication in Physical Review
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