3,143 research outputs found
Scanning SQUID Microscope Study of Vortex Polygons and Shells in Weak Pinning Disks of an Amorphous Superconducting Film
Direct observation of vortices by the scanning SQUID microscopy was made on
large mesoscopic disks of an amorphous MoGe thin film. Owing to the weak
pinning nature of the amorphous film, vortices are able to form geometry
induced, (quasi-)symmetric configurations of polygons and concentric shells in
the large disks. Systematic measurements made on selected disks allow us to
trace not only how the vortex pattern evolves with magnetic field, but also how
the vortex polygons change in size and rotate with respect to the disk center.
The results are in good agreement with theoretical considerations for
mesoscopic disks with sufficiently large diameter. A series of vortex images
obtained in a disk with a pinning site reveals a unique line symmetry in vortex
configurations, resulting in modifications of the shell filling rule and the
magic number.Comment: 8 pages, 5 figures. Phys Rev B 82 014501 (2010
Confidence intervals of prediction accuracy measures for multivariable prediction models based on the bootstrap-based optimism correction methods
In assessing prediction accuracy of multivariable prediction models, optimism
corrections are essential for preventing biased results. However, in most
published papers of clinical prediction models, the point estimates of the
prediction accuracy measures are corrected by adequate bootstrap-based
correction methods, but their confidence intervals are not corrected, e.g., the
DeLong's confidence interval is usually used for assessing the C-statistic.
These naive methods do not adjust for the optimism bias and do not account for
statistical variability in the estimation of parameters in the prediction
models. Therefore, their coverage probabilities of the true value of the
prediction accuracy measure can be seriously below the nominal level (e.g.,
95%). In this article, we provide two generic bootstrap methods, namely (1)
location-shifted bootstrap confidence intervals and (2) two-stage bootstrap
confidence intervals, that can be generally applied to the bootstrap-based
optimism correction methods, i.e., the Harrell's bias correction, 0.632, and
0.632+ methods. In addition, they can be widely applied to various methods for
prediction model development involving modern shrinkage methods such as the
ridge and lasso regressions. Through numerical evaluations by simulations, the
proposed confidence intervals showed favourable coverage performances. Besides,
the current standard practices based on the optimism-uncorrected methods showed
serious undercoverage properties. To avoid erroneous results, the
optimism-uncorrected confidence intervals should not be used in practice, and
the adjusted methods are recommended instead. We also developed the R package
predboot for implementing these methods (https://github.com/nomahi/predboot).
The effectiveness of the proposed methods are illustrated via applications to
the GUSTO-I clinical trial
Innovation Toilet and Barriers of Diffusion in Developing Country Case Study: TOTO Electronic Bidet Seat Toilet
The innovation of electronic bidet seat toilet in Japan has diffused to more than sixty percent of Japanese household while it has low rate of diffusion in other countries especially in developing country. From this phenomenon, it is interesting to understand about the barrier of diffusion, which focuses on the adopter categories of diffusion, barrier factors and proposition of key success factors of the diffusion in Indonesia as one of emerging economic and the member of G 20. There have been few studies about diffusion of innovation toilet, and this paper especially examines the diffusion of new innovations on electronic bidet toilet due to its successful diffusion among Japanese household, and further became a standard fixture toilet in Japan. This paper also discusses the product life cycle of electronic bidet toilet in Japan, global diffusion, identifies adopter categories and barrier factors of diffusion in Indonesia. Finally, theoretical propositions are developed on the diffusion of innovation for electronic bidet toilet in Indonesia
HHP1, a novel signalling component in the cross-talk between the cold and osmotic signalling pathways in Arabidopsis
Heptahelical protein 1 (HHP1) is a negative regulator in abscisic acid (ABA) and osmotic signalling in Arabidopsis. The physiological role of HHP1 was further investigated in this study using transgenic and knock-out plants. In HHP1::GUS transgenic mutants, GUS activity was found to be mainly expressed in the roots, vasculature, stomata, hydathodes, adhesion zones, and connection sites between septa and seeds, regions in which the regulation of turgor pressure is crucial. By measuring transpiration rate and stomatal closure, it was shown that the guard cells in the hhp1-1 mutant had a decreased sensitivity to drought and ABA stress compared with the WT or the c-hhp1-1 mutant, a complementation mutant of HHP1 expressing the HHP1 gene. The N-terminal fragment (amino acids 1ā96) of HHP1 was found to interact with the transcription factor inducer of CBF expression-1 (ICE1) in yeast two-hybrid and bimolecular fluorescence complementation (BiFC) studies. The hhp1-1 mutant grown in soil showed hypersensitivity to cold stress with limited watering. The expression of two ICE1-regulated genes (CBF3 and MYB15) and several other cold stress-responsive genes (RD29A, KIN1, COR15A, and COR47) was less sensitive to cold stress in the hhp1-1 mutant than in the WT. These data suggest that HHP1 may function in the cross-talk between cold and osmotic signalling
Effect of Shear Flow on the Stability of Domains in Two Dimensional Phase-Separating Binary Fluids
We perform a linear stability analysis of extended domains in
phase-separating fluids of equal viscosity, in two dimensions. Using the
coupled Cahn-Hilliard and Stokes equations, we derive analytically the
stability eigenvalues for long wavelength fluctuations. In the quiescent state
we find an unstable varicose mode which corresponds to an instability towards
coarsening. This mode is stabilized when an external shear flow is imposed on
the fluid. The effect of the shear is seen to be qualitatively similar to that
found in experiments.Comment: 13 pages, RevTeX, 8 eps figures included. Submitted to Phys. Rev.
Early stage scaling in phase ordering kinetics
A global analysis of the scaling behaviour of a system with a scalar order
parameter quenched to zero temperature is obtained by numerical simulation of
the Ginzburg-Landau equation with conserved and non conserved order parameter.
A rich structure emerges, characterized by early and asymptotic scaling
regimes, separated by a crossover. The interplay among different dynamical
behaviours is investigated by varying the parameters of the quench and can be
interpreted as due to the competition of different dynamical fixed points.Comment: 21 pages, latex, 7 figures available upon request from
[email protected]
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