2,862 research outputs found
New calculation of atmospheric neutrino fluxes
We have performed a one-dimensional Monte Carlo calculation of atmospheric neutrino fluxes in the energy range 0.05
GeVā20 GeV including muon polarization effects. It is shown that the calculated n m On e ratio does not appear
sufficient to explain the Kamiokande data from sub-GeV to multi-GeV energy region. It is suggested that neutrino oscillations would provide a solution to the anomalous n m On e ratio
Direct optical observations of surface thermal motions at sub-shot noise levels
We measure spectral properties of surface thermal fluctuations of liquids,
solids, complex fluids and biological matter using light scattering methods.
The random thermal fluctuations are delineated from random noise at sub-shot
noise levels. The principle behind this extraction, which is quite general and
is not limited to surface measurements, is explained. An optical lever is used
to measure the spectrum of fluctuations in the inclinations of surfaces down to
at W optical intensity, corresponding
to in the vertical displacement, in the
frequency range . The dynamical evolution of the
surface properties is also investigated. The measurement requires only a short
amount of time and is essentially passive, so that it can be applied to a wide
variety of surfaces.Comment: 5pp, 5 figure
Mars mission solar array Semiannual progress report, period ending 31 Dec. 1969
Design and testing of beryllium-structure solar panel for Mars missio
Predicting morphotropic phase boundary locations and transition temperatures in Pb- and Bi-based perovskite solid solutions from crystal chemical data and first-principles calculations
Using data obtained from first-principles calculations, we show that the
position of the morphotropic phase boundary (MPB) and transition temperature at
MPB in ferroelectric perovskite solutions can be predicted with quantitative
accuracy from the properties of the constituent cations. We find that the mole
fraction of PbTiO at MPB in Pb(BB)O-PbTiO,
BiBO-PbTiO and Bi(BB)O-PbTiO exhibits a linear
dependence on the ionic size (tolerance factor) and the ionic displacements of
the B-cations as found by density functional theory calculations. This
dependence is due to competition between the local repulsion and A-cation
displacement alignment interactions. Inclusion of first-principles displacement
data also allows accurate prediction of transiton temperatures at the MPB. The
obtained structure-property correlations are used to predict morphotropic phase
boundaries and transition temperatures in as yet unsynthesized solid solutions.Comment: Accepted for publication in J. Appl. Phy
Domain Size Dependence of Piezoelectric Properties of Ferroelectrics
The domain size dependence of piezoelectric properties of ferroelectrics is
investigated using a continuum Ginzburg-Landau model that incorporates the
long-range elastic and electrostatic interactions. Microstructures with desired
domain sizes are created by quenching from the paraelectric phase by biasing
the initial conditions. Three different two-dimensional microstructures with
different sizes of the domains are simulated. An electric field is
applied along the polar as well as non-polar directions and the piezoelectric
response is simulated as a function of domain size for both cases. The
simulations show that the piezoelectric coefficients are enhanced by reducing
the domain size, consistent with recent experimental results of Wada and
Tsurumi (Brit. Ceram. Trans. {\bf 103}, 93, 2004) on domain engineered
Comment: submitted to Physical Review
Bayesian inference with an adaptive proposal density for GARCH models
We perform the Bayesian inference of a GARCH model by the Metropolis-Hastings
algorithm with an adaptive proposal density. The adaptive proposal density is
assumed to be the Student's t-distribution and the distribution parameters are
evaluated by using the data sampled during the simulation. We apply the method
for the QGARCH model which is one of asymmetric GARCH models and make empirical
studies for for Nikkei 225, DAX and Hang indexes. We find that autocorrelation
times from our method are very small, thus the method is very efficient for
generating uncorrelated Monte Carlo data. The results from the QGARCH model
show that all the three indexes show the leverage effect, i.e. the volatility
is high after negative observations
Lipocortin I (Annexin I) Is Preferentially Localized on the Plasma Membrane in Keratinocytes of Psoriatic Lesional Epidermis as Shown by Immunofluorescence Microscopy
Lopocortin I (LPC-I, also called annexin I) is a 35-kD protein that binds phospholidpids and actin ina a Ca++-dependetn manner. It is also a major substrate for EGF recepto/kinase and rotein kinase C,. and a putative inhibito of phospholipase A2, which produces chemical mediators to cause inflammation. Psoriasos (PS) is an inflammatory skin disease characterized by a rapid turnover of keratinocytes and a defect in keratinization with increased activities of phospholipase C and A2, and EGF receptor. To understand the mechanism of the PS lesion formation and the function of LPC-I, its didtribution was studied in the epiedermis of PS, subacure eczema and normal skin, and in tumor, cells of seborheic keratosis and Bowen's disease. This study involved immunofluorescence and immunoblotting using affinity-purified polyclonal and monclonal antibodies specific to LPC-I and to its Ca++- bound form. In normal, nonlesional PS and subacute eczema epidermis, LPC-I was detected , mainly in the cytoplasm of the suprabasal cells, although it was on the inner aspects of the plasma membrane in some parts of the granular layer. In lesional epidermis of PS it was localized mainly on the inner aspects of the plasma membrane, but not in the cytoplasm of the whole suprabasal cells as the Ca++-bond form, indicating a preferential localization of the plasma membrane. This membrane-binding of LPC-I was also observed in seborrheic keratosis, but not in Bowen's disease. These results suggest that the binding of LPC-I to the plasma membrane occurs actually in living cells, plays a role not necessarily disease specific, in the PS lesion formation, and has some relevance to normal or abnormal differentiation of keratinocytes
Background light measurements at the DUMAND site
Ambient light intensities at the DUMAND site, west of the island of Hawaii were measured around the one photoelectron level. Throughout the water column between 1,500m and 4,700m, a substantial amount of stimulateable bioluminescence is observed with a ship suspended detector. But non-stimulated bioluminescence level is comparable, or less than, K sup 40 background, when measured with a bottom tethered detector typical of a DUMAND optical module
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