2,507 research outputs found

    Consistent Estimation of Mixed Memberships with Successive Projections

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    This paper considers the parameter estimation problem in Mixed Membership Stochastic Block Model (MMSB), which is a quite general instance of random graph model allowing for overlapping community structure. We present the new algorithm successive projection overlapping clustering (SPOC) which combines the ideas of spectral clustering and geometric approach for separable non-negative matrix factorization. The proposed algorithm is provably consistent under MMSB with general conditions on the parameters of the model. SPOC is also shown to perform well experimentally in comparison to other algorithms

    Second-order Nonlinear Optical Microscopy of Spider Silk

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    Asymmetric β\rm \beta-sheet protein structures in spider silk should induce nonlinear optical interaction such as second harmonic generation (SHG) which is experimentally observed for a radial line and dragline spider silk by using an imaging femtosecond laser SHG microscope. By comparing different spider silks, we found that the SHG signal correlates with the existence of the protein β\rm \beta-sheets. Measurements of the polarization dependence of SHG from the dragline indicated that the β\rm \beta-sheet has a nonlinear response depending on the direction of the incident electric field. We propose a model of what orientation the β\rm \beta-sheet takes in spider silk.Comment: 8 pages, 8 figures, 1 tabl

    Sum frequency generation spectroscopy of the attachment disc of a spider

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    The pyriform silk of the attachment disc of a spider was studied using infrared-visible vibrational sum frequency generation (SFG) spectroscopy. The spider can attach dragline and radial lines to many kinds of substrates in nature (concrete, alloy, metal, glass, plant branches, leaves, etc.) with the attachment disc. The adhesion can bear the spider's own weight, and resist the wind on its orb web. From our SFG spectroscopy study, the NH group of arginine side chain and/or NH2_{2} group of arginine and glutamine side chain in the amino acid sequence of the attachment silk proteins are suggested to be oriented in the disc. It was inferred from the observed doublet SFG peaks at around 3300 cm−1^{-1} that the oriented peptide contains two kinds of structures.Comment: 21 pages, 8 figure

    Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration

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    We investigate the transport properties of LixCoO2 thin films whose resistivities are nearly an order of magnitude lower than those of the bulk polycrystals. A metal-nonmetal transition occurs at ~0.8 in a biphasic domain, and the Seebeck coefficient (S) is drastically increased at ~140 K (= T*) with increasing the Li concentration to show a peak of magnitude ~120 \muV/K in the S-T curve of x = 0.87. We show that T* corresponds to a crossover temperature in the conduction, most likely reflecting the correlation-induced temperature dependence in the low-energy excitations

    Numerical analysis of tsunami-induced inundation behind building along coasts

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    To evaluate the effects of impermeable rigid buildings located near vertical quay walls on the reduction of the inundation water volumes due to run-up tsunamis, a full-scale three-dimensional numerical analysis is performed using a three-dimensional coupled fluid-structure-sediment interaction model. Numerical results show that the inundation water volume can be reduced with an increase in the shielding ratio of the long-shore width of the buildings with respect to the total width of the coastline, and accordingly the buildings located along the coasts have the reduction effects of the inundation water volume. This suggests that countermeasures against tsunamis can be evaluated in a\ud comprehensive manner in terms of not only shore protection facilities for tsunamis at relatively high frequencies but also such buildings. Furthermore, the inundation depth at the seaward side of the buildings and the cross-shore bottom flow velocity at the gaps between the buildings increase with the shielding ratio, suggesting an increase in tsunami force and the onset of local scouring when the shielding ratio is large. Consequently, when designing buildings along the coasts, it is essential to consider an appropriate balance between the reduction effects of the inundation water volume and the instability of the buildings caused by the tsunami force and the local scouring

    Composition of primary cosmic rays at energies 10(15) to approximately 10(16) eV

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    The sigma epsilon gamma spectrum in 1 approx. 5 x 1000 TV observed at Mt. Fuji suggests that the flux of primary protons 10 to the 15 approx 10th eV is lower by a factor of 2 approx. 3 than a simple extrapolation from lower energies; the integral proton spectrum tends to be steeper than around to the power V and the spectral index tends to be steeper than Epsilon to the -17th power around 10 to the 14th power eV and the spectral index becomes approx. 2.0 around 10 to the 15th power eV. If the total flux of primary particles has no steepening up to approx 10 to the 15th power eV, than the fraction of primary protons to the total flux should be approx 20% in contrast to approx 45% at lower energies

    High energy gamma-rays and hadrons at Mount Fuji

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    The energy spectra of high energy gamma-rays and hadrons were obtained by the emulsion chamber with 40 c.u. thickness at Mt. Fuji (3750 m). These results are compared with the Monte Carlo calculation based on the same model which is used in a family analysis. Our data are compatible with the model of heavy-enriched primary and scaling in the fragmentation region

    Particle interactions at energies over 1000 TeV inferred from gamma-families observed at Mount Fuji

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    Scaling, mean P sub t, high P sub t jets and others at energies over 1000 TeV are discussed on the basis of gamma-family data with sigma E sub gamma 100 TeV, observed at Mt. Fuji (3750 m). These quantities were examined in connection with the primary composition

    Urban Diabetic Women\u27s Perception of Healthy Eating Lifestyles From West Java

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    This study aimed to explore perceptions about a healthy-eating lifestyle and reasons to practice a healthy-eating lifestyle of women with type 2 diabetes in a city of West Java by using a case study design. Six female patients, with type 2 diabetes, ages 47–63 from a hospital were interviewed guided by the health promotion model. Their healthy-eating lifestyle included currently practicing or not practicing a healthy-eating lifestyle. Reasons to practice were: beliefs for health and for physical energy to work for family, definition of multidimensional health and self-efficacy increased by: support from God, support from family, support from health professionals and improved or deteriorated health status by prior experience. Reasons not to practice were: difficulty in arranging diet, rejecting eating, controlling appetite, and accessing health care services. Related difficulties were interpersonal relations with family and social situation such as social events, expensive medical fee, and distance to the hospital. These findings suggest that women with type 2 diabetes in Indonesia need to be supported with the reasons to practice a healthy-eating lifestyle
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