2,862 research outputs found

    New calculation of atmospheric neutrino fluxes

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    We have performed a one-dimensional Monte Carlo calculation of atmospheric neutrino fluxes in the energy range 0.05 GeVā€“20 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

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    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 āˆ¼10āˆ’17rad2/Hz\sim 10^{-17}\rm rad^2/Hz at 1āˆ¼10Ī¼1\sim10 \muW optical intensity, corresponding to āˆ¼10āˆ’29m2/Hz\sim 10^{-29} \rm m^2/\rm Hz in the vertical displacement, in the frequency range 1kHzāˆ¼10MHz1{\rm}\rm kHz\sim10 MHz. 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

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    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

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    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 PbTiO3_3 at MPB in Pb(Bā€²'Bā€²ā€²'')O3_3-PbTiO3_3, BiBO3_3-PbTiO3_3 and Bi(Bā€²'Bā€²ā€²'')O3_3-PbTiO3_3 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

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    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 90o90^{o} 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 BaTiO3BaTiO_{3} Comment: submitted to Physical Review

    Bayesian inference with an adaptive proposal density for GARCH models

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    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

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    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

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    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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