Review on Slip Transmission Criteria in Experiments and Crystal Plasticity Models

A comprehensive overview is given of the literature on slip transmission criteria for grain boundaries in metals, with a focus on slip system and grain boundary orientation. Much of this extensive literature has been informed by experimental investigations. The use of geometric criteria in continuum crystal plasticity models is discussed. The theoretical framework of Gurtin (2008, J. Mech. Phys. Solids 56, p. 640) is reviewed for the single slip case. This highlights the connections to slip transmission criteria from the literature that are not discussed in the work itself. Different geometric criteria are compared for the single slip case with regard to their prediction of slip transmission. Perspectives on additional criteria, investigated in experiments and used in computational simulations, are given.Comment: in Journal of Materials Science, 201

Decreasing Opportunities for Low-Wage Workers: The Role of the Nondiscrimination Law for Employer-Provided Health Insurance

As of 1978, the favorable tax treatment of fringe benefits, including health insurance, has been regulated via a nondiscrimination clause such that low-wage, full-time workers must be offered health insurance (and other benefits) that are offered to higher-wage workers by the firm. Part-time workers may be excluded from coverage, however, creating incentives for firms to hire some types of workers part time to deny them coverage. We hypothesize that firms will hire fewer workers whose relative costs have increased, that is, low-wage workers. These workers will be less likely to work for firms that offer coverage, and those that do will be more likely to work part time without being eligible for the firm’s health insurance benefits. We use the 1988 and 1993 Employee Benefits Supplements to the Current Population Surveys and an employer premium imputation to examine these hypotheses. Both the descriptive and multivariate analysis are consistent with our hypotheses. We predict the probability of working for a firm that offers health insurance to decrease as premiums increase for both high- and low-wage workers. An increase in the premium is also associated with a decrease in the probability of part-time work, but an even greater decrease in the joint probability of part-time work with eligibility for health insurance.

An ontology for ISO software engineering standards: 1) Creating the infrastructure

Software engineering standards developed under the auspices of ISO/IEC JTC1's SC7 have been identified as employing terms whose definitions vary significantly between standards. This led to a request in 2012 to investigate the creation of an ontological infrastructure that aims to be a single coherent underpinning for all SC7 standards, present and future. Here, we develop that necessary infrastructure prior to its adoption by SC7 and its implementation (likely 2014). The proposal described here requires, firstly, the identification of a single comprehensive set of definitions, the definitional elements ontology (DEO). For the scope of an individual standard, only a subset of these definitional elements will be needed. Once configured, this definitional subset creates a configured definitional ontology or CDO. Both the DEO and the CDO are essentially foundational ontologies from which a domain-specific ontology known as a SDO or standard domain ontology can be created. Consequently, all such SDOs are conformant to a CDO and hence to the single DEO thus ensuring that all standards use the same ontological base. Standards developed in this fashion will therefore be not only of a higher quality but also, importantly, interoperable. © 2013 Elsevier B.V. All rights reserved

Computational and Theoretical Aspects of a Grain-Boundary Model at Finite Deformations

A model to describe the role of grain boundaries in the overall response of a polycrystalline material at small length scales subject to finite deformations is presented. Three alternative thermodynamically consistent plastic flow relations on the grain boundary are derived and compared using a series of numerical experiments. The numerical model is obtained by approximating the governing relations using the finite element method. In addition, the infinitesimal and finite deformation theories are compared, and the limitations of the former made clear

Pharmacological And Genetic Reversal Of Age-Dependent Cognitive Deficits Attributable To Decreased Presenilin Function

Alzheimer\u27s disease (AD) is the leading cause of cognitive loss and neurodegeneration in the developed world. Although its genetic and environmental causes are not generally known, familial forms of the disease (FAD) are attributable to mutations in a single copy of the Presenilin (PS) and amyloid precursor protein genes. The dominant inheritance pattern of FAD indicates that it may be attributable to gain or change of function mutations. Studies of FAD-linked forms of presenilin (psn) in model organisms, however, indicate that they are loss of function, leading to the possibility that a reduction in PS activity might contribute to FAD and that proper psn levels are important for maintaining normal cognition throughout life. To explore this issue further, we have tested the effect of reducing psn activity during aging in Drosophila melanogaster males. We have found that flies in which the dosage of psn function is reduced by 50% display age-onset impairments in learning and memory. Treatment with metabotropic glutamate receptor (mGluR) antagonists or lithium during the aging process prevented the onset of these deficits, and treatment of aged flies reversed the age-dependent deficits. Genetic reduction of Drosophila metabotropic glutamate receptor (DmGluRA), the inositol trisphosphate receptor (InsP(3)R), or inositol polyphosphate 1-phosphatase also prevented these age-onset cognitive deficits. These findings suggest that reduced psn activity may contribute to the age-onset cognitive loss observed with FAD. They also indicate that enhanced mGluR signaling and calcium release regulated by InsP(3)R as underlying causes of the age-dependent cognitive phenotypes observed when psn activity is reduced