Braneworld inflation driven by dynamics of a bulk scalar field

We review a viable alternative scenario of the inflationary universe in the context of the Randall-Sundrum (RS) braneworld. In this scenario, the dynamics of a 5-dimensional scalar field, which we call a bulk scalar field, plays the central role. Focusing on the second (single-brane) RS model, we discuss braneworld inflation driven by a bulk scalar field without introducing an inflaton on the brane. As a toy model, for the bulk scalar field, we consider a minimally coupled massive scalar field in the 5-dimensional spacetime, and look for a perturbative solution of the field equation in the anti-de Sitter background with an inflating brane. For a suitable range of the model parameters, we find a solution that realizes slow-roll inflation on the brane. When the Hubble parameter on the brane and the mass of a bulk scalar field are much smaller than a typical 5-dimensional mass scale, it is found that this proposed inflation scenario reproduces the standard inflation scenario in the 4-dimensional theory.Comment: 10 pages, 1 figure, 1 reference added, typos corrected, to be published in Progress of Theoretical Physics Supplement No. 148 "Brane World: New Perspective in Cosmology

Ab initio Study of Valley Line on a Total-Energy Surface for Zone-Center Distortions of Ferroelectric Perovskite Oxides BaTiO3 and PbTiO3

An ab initio structure optimization technique is newly developed to determine the valley line on a total-energy surface for zone-center distortions of ferroelectric perovskite oxides and is applied to barium titanate BaTiO3 and lead titanate PbTiO3. The proposed technique is an improvement over King-Smith and Vanderbilt's scheme [Phys. Rev. B 49, p.5828 (1994)] of evaluating total energy as a function of the amplitude of atomic displacements. The results of numerical calculations show that total energy can be expressed as a fourth-order function of the amplitude of atomic displacements in BaTiO3 but not in PbTiO3.Comment: 4 pages, 5 figure

ab initio Study of Strain-Induced Ferroelectricity in SrTiO3

Valley lines on total-energy surfaces for the zone-center distortions of free-standing and in-plane strained SrTiO3 are investigated with a newly developed first-principles structure optimization technique [Jpn. J. Appl. Phys. vol.43 (2004), p.6785]. The results of numerical calculations confirmed that the ferroelectricity is induced, and the Curie temperature is increased, by applying biaxial compressive or tensile strains. Along the distortion, strong nonlinear coupling between the soft- and hard-modes is demonstrated.Comment: 15 pages, 10 figures, submitted to Jpn. J. Appl. Phy

Greater Disruption Due to Failure of Inhibitory Control on an Ambiguous Distractor

Considerable evidence indicates that a stimulus that is subthreshold, and thus consciously invisible, influences brain activity and behavioral performance. However, it is not clear how subthreshold stimuli are processed in the brain. We found that a task-irrelevant subthreshold coherent motion led to a stronger disturbance in task performance than did suprathreshold motion. With the subthreshold motion, activity in the visual cortex measured by functional magnetic resonance imaging was higher, but activity in the lateral prefrontal cortex was lower, than with suprathreshold motion. These results suggest that subthreshold irrelevant signals are not subject to effective inhibitory control

Compressibility of Liquefied Sand

Laboratory measurement using CCD camera was conducted to trace the sedimentation process of sand grains in a liquefied model layer. The purpose of this measurement was basically intended to obtain a visual evidence of appearance of suspended state in upper part of the liquefied soil. For this purpose, glass bead particles were used as model ground material. The test results prevailed that the glass bead grains were suspended in pore water at the instant when complete liquefaction was brought about to the layer, then they began to settle in the water. The measured pore water kept high value until grains ceased moving. And the moving velocity was far slower than that estimated by Stokes equation for sedimentation of single particle. From these findings, a predicting method was proposed to obtain the compressibility of liquefied sand layer and the continuation time of suspended state of grains

Associação do cloridrato de dexmedetomidina à infusão contínua de propofol durante cirurgia cardíaca com circulação extracorpórea em carneiros /

Orientador: Metry BacilaDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Ciencias Veterinárias. Defesa: Curitiba, 2006Inclui bibliografi