An investigation of the beneficial effects of adding carbon nanotubes to standard injection grout

Mortar grouting is often used in masonry constructions to mitigate structural decay and repair damage by filling cracks and voids, resulting in an improvement in mechanical properties. This paper presents an original experimental investigation on grout with added carbon nanotubes (CNTs). The samples were prepared with different percentages of CNTs, up to 1.2 wt% with respect to the binder, and underwent three‐point bending tests in crack mouth opening displacement mode and compressive tests. The results showed that very small additions (up to 0.12 wt% of CNTs) increased not only flexural and compressive strengths (+73% and 35%, respectively, in comparison with plain mortar) but also fracture energy (+80%). These results can be explained on the basis of a reduction in porosity, as evidenced by mercury intrusion porosimetry, as well as by a crack bridging mechanism and by the probable formation of nucleation sites for hydration products, as observed through scanning electron microscopy

Venezuela's Growth Experience

The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain between 80 to 95 percent of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.Productivity, physical capital, misallocation, policies

Improving Care for Individuals With Limited English Proficiency: Facilitators and Barriers to Providing Language Services in California Public Hospitals

Evaluates twelve public hospitals' efforts to improve language services for patients with limited English proficiency: policies and procedures, organizational commitment, strategies for change, training, effectiveness, and facilitators and barriers

On the consistency of the Horava Theory

With the goal of giving evidence for the theoretical consistency of the Horava Theory, we perform a Hamiltonian analysis on a classical model suitable for analyzing its effective dynamics at large distances. The model is the lowest-order truncation of the Horava Theory with the detailed-balance condition. We consider the pure gravitational theory without matter sources. The model has the same potential term of general relativity, but the kinetic term is modified by the inclusion of an arbitrary coupling constant lambda. Since this constant breaks the general covariance under space-time diffeomorphisms, it is believed that arbitrary values of lambda deviate the model from general relativity. We show that this model is not a deviation at all, instead it is completely equivalent to general relativity in a particular partial gauge fixing for it. In doing this, we clarify the role of a second-class constraint of the model.Comment: The wording has been revised in general, specially in abstract, introduction and conclusions. No changes in results. Version published in IJMP

Hospital implementation of health information technology and quality of care: are they related?

Recently, there has been considerable effort to promote the use of health information technology (HIT) in order to improve health care quality. However, relatively little is known about the extent to which HIT implementation is associated with hospital patient care quality. We undertook this study to determine the association of various HITs with: hospital quality improvement (QI) practices and strategies; adherence to process of care measures; risk-adjusted inpatient mortality; patient satisfaction; and assessment of patient care quality by hospital quality managers and front-line clinicians.This work was supported by a grant from the Commonwealth Fund. We are indebted to Anthony Shih and Anne-Marie Audet of the Fund for their advice, support, and constructive suggestions throughout the design and conduct of the study. We thank our colleagues - Raymond Kang, Peter Kralovec, Sally Holmes, Frances Margolin, and Deborah Bohr - for their valuable contributions to the development of the QAS, the CPS, and the database on which the analytic findings reported here were based. We also thank 3 M (TM) Health Information Systems' for use of its All Patient Refined Diagnosis Related Groups (APR-DRGs) software. We especially wish to thank Jennifer Drake for her contributions not only to survey development, but also to earlier analysis of survey findings relevant to this paper. (Commonwealth Fund)Published versio

Venezuela’s Growth Experience

The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain a large portion of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.Productivity, physical capital, misallocation, policies

On Non Commutative G2 structure

Using an algebraic orbifold method, we present non-commutative aspects of $G_2$ structure of seven dimensional real manifolds. We first develop and solve the non commutativity parameter constraint equations defining $G_2$ manifold algebras. We show that there are eight possible solutions for this extended structure, one of which corresponds to the commutative case. Then we obtain a matrix representation solving such algebras using combinatorial arguments. An application to matrix model of M-theory is discussed.Comment: 16 pages, Latex. Typos corrected, minor changes. Version to appear in J. Phys.A: Math.Gen.(2005

Remarks on the Scalar Graviton Decoupling and Consistency of Horava Gravity

Recently Horava proposed a renormalizable gravity theory with higher derivatives by abandoning the Lorenz invariance in UV. But there have been confusions regarding the extra scalar graviton mode and the consistency of the Horava model. I reconsider these problems and show that, in the Minkowski vacuum background, the scalar graviton mode can be consistency decoupled from the usual tensor graviton modes by imposing the (local) Hamiltonian as well as the momentum constraints.Comment: Some clarifications regarding the projectable case added, Typos corrected, Comments (Footnote No.9, Note Added) added, References updated, Accepted in CQ

Non Abelian BF theories with sources and 2-D gravity

We study the interaction of non-Abelian topological $BF$ theories defined on two dimensional manifolds with point sources carrying non-Abelian charges. We identify the most general solution for the field equations on simply and multiply connected two-manifolds. Taking the particular choice of the so-called extended Poincar\'e group as the gauge group we discuss how recent discussions of two dimensional gravity models do fit in this formalism.Comment: 20 pages, Latex, To appear in Phys Rev D5

Non Abelian TQFT and scattering of self dual field configuration

A non-abelian topological quantum field theory describing the scattering of self-dual field configurations over topologically non-trivial Riemann surfaces, arising from the reduction of 4-dim self-dual Yang-Mills fields, is introduced. It is shown that the phase space of the theory can be exactly quantized in terms of the space of holomorphic structures over stable vector bundles of degree zero over Riemann surfaces. The Dirac monopoles are particular static solutions of the field equations. Its relation to topological gravity is discussed.Comment: 13 pages, Late