Finite-size effects in lead scandium tantalate relaxor thin films

Large electromechanical effects in relaxor ferroelectrics are generally attributed to the collective response of an ensemble of correlated, nanometer-sized polar structures induced by chemical and charge disorder. Here, we study finite-size effects on such polar order (i.e., how it evolves when sample dimensions approach the polarization correlation length) in 7-70-nm-thick films of the relaxor ferroelectric PbSc0.5Ta0.5O3. Temperature-dependent polarization studies reveal a linear suppression of the polarization and nonlinearity associated with relaxor order as the film thickness decreases to ≈30 nm. Below this thickness, however, the suppression rapidly accelerates, and polarization is completely absent by film thicknesses of ≈7 nm, despite the continued observation of a broad peak in dielectric permittivity and frequency dispersion. Diffuse-scattering measurements reveal the diffuse-scattering symmetry, and analysis suggests the films have a polarization correlation length of ≈23 nm. Taken together, it is apparent that reduction of sample size and the resulting distribution of polar structures drive suppression and eventual quenching of the electrical response of relaxors, which may be attributed to increasing dipole-dipole and dipole-interface interactions

Hall viscosity from gauge/gravity duality

In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.Comment: 12 page

Assessment of Ubiquitous Healthcare Information Systems Benefits

Health is a fully individualized concern, and is therefore inherently mobile. Thus, Ubiquitous Healthcare Information Systems can enable a much-needed patient-centered care environment. This paper presents a decision support system that makes use of system dynamics methodologies in order to assess the improved health benefits that may be realized within the context of ubiquitous healthcare information systems in support of managing diabetes

Motivating CIO Advice Networking to Improve Firm Performance

Prior research has examined factors that motivate executives in general to seek advice from external peers. The literature is silent however regarding what IT governance mechanisms motivate CIOs to mindfully seek advice in their external advice networks. Our research shows that simply applying the advice of the prior literature in the CIO and IT governance context can be counterproductive. We analyze data from a survey of 99 municipal corporations to show that an effective configuration of IT governance mechanisms fits and changes over time with the firm’s financial performance and state of IT enactment. The lessons learned are instructive for practitioners, while also highlighting the importance of attending to context in IT governance research

The Viscosity Bound Conjecture and Hydrodynamics of M2-Brane Theory at Finite Chemical Potential

Kovtun, Son and Starinets have conjectured that the viscosity to entropy density ratio $\eta/s$ is always bounded from below by a universal multiple of $\hbar$ i.e., $\hbar/(4\pi k_{B})$ for all forms of matter. Mysteriously, the proposed viscosity bound appears to be saturated in all computations done whenever a supergravity dual is available. We consider the near horizon limit of a stack of M2-branes in the grand canonical ensemble at finite R-charge densities, corresponding to non-zero angular momentum in the bulk. The corresponding four-dimensional R-charged black hole in Anti-de Sitter space provides a holographic dual in which various transport coefficients can be calculated. We find that the shear viscosity increases as soon as a background R-charge density is turned on. We numerically compute the few first corrections to the shear viscosity to entropy density ratio $\eta/s$ and surprisingly discover that up to fourth order all corrections originating from a non-zero chemical potential vanish, leaving the bound saturated. This is a sharp signal in favor of the saturation of the viscosity bound for event horizons even in the presence of some finite background field strength. We discuss implications of this observation for the conjectured bound.Comment: LaTeX, 26+1 Pages, 4 Figures, Version 2: references adde

Shear viscosity from R-charged AdS black holes

We compute the shear viscosity in the supersymmetric Yang-Mills theory dual to the STU background. This is a thermal gauge theory with a chemical potential. The quotient of the shear viscosity over the entropy density exhibits no deviation from the well known result 1/4\pi.Comment: 9 pages, some references updated, abstract and some typos correcte

iGlarLixi effectively reduces residual hyperglycaemia in patients with type 2 diabetes on basal insulin: A post hoc analysis from the LixiLan-L study

Globally, nearly half of patients with type 2 diabetes (T2D) do not successfully achieve target HbA1c with basal insulin, despite meeting fasting plasma glucose (FPG) targets. In this post hoc analysis of the LixiLan-L study, we determined whether iGlarLixi, a fixed-ratio combination of insulin glargine Gla-100 (iGlar) and the glucagon-like peptide-1 receptor agonist lixisenatide (Lixi), addresses the challenge of reducing residual hyperglycaemia in patients with T2D. In LixiLan-L, a randomized, open-label study, 1018 patients with T2D on basal insulin for ≥6 months ± oral antidiabetes drugs entered a 6-week run-in period, during which they were switched to and/or optimized for a daily dose of iGlar while continuing only metformin. Following the run-in period, 736 patients were then randomized to receive iGlarLixi or were continued on iGlar for 30 weeks ± metformin. Residual hyperglycaemia was defined as HbA1c ≥ 7.0% despite FPG of <140 mg/dL. The proportion of patients with residual hyperglycaemia was similar in both treatment arms at screening (~~42%), and increased after the run-in period (~~62%). After 30 weeks, the proportion of patients with residual hyperglycaemia declined to 23.8% in the iGlarLixi versus 47.1% in the iGlar arm (P <.0001). The proportion of patients achieving both HbA1c (<7.0%) and FPG (<140 mg/dL) targets was higher in the iGlarLixi compared with the iGlar arm (50.3% vs. 27.4%, respectively; P <.0001). iGlarLixi effectively reduces residual hyperglycaemia in patients with T2D on basal insulin therapy

Black Hole Entropy and Superconformal Field Theories on Brane-Antibrane Systems

We obtain the enropy of Schwarzschild and charged black holes in D>4 from superconformal gases that live on p=10-D dimensional brane-antibrane systems wrapped on T^p. The preperties of the strongly coupled superconformal theories such as the appearance of hidden dimensions (for p=1,4) and fractional strings (for p=5) are crucial for our results. In all cases, the Schwarzschild radius is given by the transverse fluctuations of the branes and antibranes due to the finite temperature. We show that our results can be generalized to multicharged black holes.Comment: 24 pages in phyzzx.te