Instrumental variable (IV) methods are widely used to deal with the issue of unmeasured confounding and are becoming popular in health and medical research. IV models are able to obtain consistent estimates in the presence of unmeasured confounding, but rely on assumptions that are hard to verify and often criticized. An instrument is a variable that influences or encourages individuals toward ...

We demonstrate how an exponentially saturating increase of the contact area between a nanoasperity and a crystal surface, occurring on time scales governed by the Arrhenius equation, is consistent with measurements of the static friction and lateral contact stiffness on a model alkali-halide surface at different temperatures in ultrahigh vacuum. The "contact ageing" effect is attributed to atom...

Many health experts worry that the dra matic health gains of recent years may prove temporary if external resources wane. The U.S. Global Health Initiative (GHI) outlines an ambitious agenda to permanently strengthen the health systems of the countries we assist, but there is no consensus on how to do this. One promising approach applies the lessons learned from improving care in the U.S. healt...

Frictional interfaces abound in natural and man-made systems, yet their dynamics are not well-understood. Recent extensive experimental data have revealed that velocity-strengthening friction, where the steady-state frictional resistance increases with sliding velocity over some range, is a generic feature of such interfaces. This physical behavior has very recently been linked to slow stick-sl...

BACKGROUND Total knee replacement (TKR) is the commonest surgical procedure for patients with severe pain and impaired physical function following end stage knee osteoarthritis. The hip abductors are well renowned in stabilization of the trunk and hip during walking, maintaining the lower limb position, and transferring the forces from the lower limbs to the pelvis. OBJECTIVE To assess the ef...

BACKGROUND Aerobic and muscle-strengthening activities are related to morbidities and mortality. Resistance exercise/strength training items are included in national surveys, but the manner in which muscle-strengthening activity is queried varies among these surveys. PURPOSE The purpose of this study was to use different self-report measures to examine the prevalence of meeting the 2008 Physi...

At present there exist numerous, approved documents and guidelines across Europe, the US, Japan and Canada, giving detailed information on the various applications available that provide for the strengthening of concrete structures with Fibre Reinforced Polymers (FRP). Such guidelines offer a detailed overview of the principles involved in the design of strengthening for deficient beams, column...

A centrifugal force-based adhesion assay has been used to quantitatively examine the kinetics of formation of cell-cell contacts mediated specifically by expression of E-cadherin under the control of a glucocorticoid-inducible promoter in mouse fibroblasts. Analysis of cells expressing maximal or minimal levels of E-cadherin showed that the strength of E-cadherin-mediated adhesion developed in ...

We explore the role of the acoustic consequences of domain-initial strengthening in spoken-word recognition. In two cross-modal identity-priming experiments, listeners heard sentences and made lexical decisions to visual targets, presented at the onset of the second word in two-word sequences containing lexical ambiguities (e.g., bus tickets, with the competitor bust). These sequences contained...

Strengthening or destroying a network is a very important issue in designing resilient networks or in planning attacks against networks, including planning strategies to immunize a network against diseases, viruses, etc. Here we develop a method for strengthening or destroying a random network with a minimum cost. We assume a correlation between the cost required to strengthen or destroy a node...