Understanding Evolutionary Potential in Virtual CPU Instruction Set Architectures

We investigate fundamental decisions in the design of instruction set architectures for linear genetic programs that are used as both model systems in evolutionary biology and underlying solution representations in evolutionary computation. We subjected digital organisms with each tested architecture to seven different computational environments designed to present a range of evolutionary challenges. Our goal was to engineer a general purpose architecture that would be effective under a broad range of evolutionary conditions. We evaluated six different types of architectural features for the virtual CPUs: (1) genetic flexibility: we allowed digital organisms to more precisely modify the function of genetic instructions, (2) memory: we provided an increased number of registers in the virtual CPUs, (3) decoupled sensors and actuators: we separated input and output operations to enable greater control over data flow. We also tested a variety of methods to regulate expression: (4) explicit labels that allow programs to dynamically refer to specific genome positions, (5) position-relative search instructions, and (6) multiple new flow control instructions, including conditionals and jumps. Each of these features also adds complication to the instruction set and risks slowing evolution due to epistatic interactions. Two features (multiple argument specification and separated I/O) demonstrated substantial improvements int the majority of test environments. Some of the remaining tested modifications were detrimental, thought most exhibit no systematic effects on evolutionary potential, highlighting the robustness of digital evolution. Combined, these observations enhance our understanding of how instruction architecture impacts evolutionary potential, enabling the creation of architectures that support more rapid evolution of complex solutions to a broad range of challenges

Prediction of In-Plane Stiffnesses and Thermomechanical Stresses in Cylindrical Composite Cross-Sections

Accurate mechanical analysis of composite structures is necessary for the prediction of laminate behavior. Cylindrical composite tubes are a mainstay in many structural applications. The fundamental design of circular composite cross-sections necessitates the development of a comprehensive composite lamination theory. A new analytical method is developed to characterize the behavior of thin-walled composite cylindrical tubes using a modified plate theory. A generated numerical solver can predict properties such as axial stiffness, bending stiffness, layer stresses, and layer strains in composite tubes subjected to combined mechanical loading and thermal effects. The model accounts for the curvature by transforming and translating the material in-plane lamina properties over a global reference coordinate system. A MATLAB-based solver is used to determine the lamina stiffness and stress outcomes with adjustable parameters, including elastic material properties, thermal coefficients, tubing radius, the orientation of fibers, and the ply stacking sequence. The results are then validated using a FE model developed in ABAQUS using a simple quadrature S4R element type. Parametric case studies confirm the validity of the analytical model by accounting for different ply orientations, stacking sequence, and thermal, mechanical loading

Soil penetrometer

An auger-type soil penetrometer for burrowing into soil formations is described. The auger, while initially moving along a predetermined path, may deviate from the path when encountering an obstruction in the soil. Alterations and modifications may be made in the structure so that it may be used for other purposes

Schlumberger Technology Corp. v. United States

Published in cooperation with the American Bar Association Section of Dispute Resolutio

Are you a researcher as well as a medical illustrator?

When we list the areas of practice for medical illustrators we always include research, but how involved in research are we? The aim of this activity is to encourage your professional development not just as a medical illustrator but your involvement with research whether that is undertaking your own research, undertaking evidence based practice (1) , working as part of a research team, advising researchers on the value of medical illustration or supporting a student undertaking a research project for their degree or post-graduate qualification

Cultivating Curiosity and Collaboration: Mentalizing as a Modality of Intervention in Attention-Deficit/Hyperactivity Disorder

Parents and caregivers who are able to understand their own mental states are better able to hold a child’s mental states in mind, an important consideration for moderating negative perceptions of ADHD behavior. In this thesis, I discuss how mentalizing-focused treatment for parents and caregivers strengthens attachment bonds in families where a child is diagnosed with ADHD. I explore the effectiveness of mentalizing-focused treatment to parents, some of whom experience difficulty in understanding their own mental states, and all of whom experience challenges in interpreting the intentions and mental states of their children, particularly in families where a child has been diagnosed with ADHD. In addition, I define how mentalizing relates to the important developmental theories, including attachment, as a means of promoting autonomy and resilience for a child as well as the potential negative effects when mentalizing breaks down

New deal for young people: national survey of participants: stage 1

This report covers the early experiences of participants‚ of New Deal for Young People aged 18-24 years, based on the first wave of a two wave nationally representative survey of entrants to the programme. It looks at participants experiences approximately 6 months after programme entry and covers mainly the gateway and early Options stag

Has performance pay increased wage inequality in Britain?

Using data from the British Household Panel Survey (BHPS) we show performance pay (PP) increased earnings dispersion among men and women, and to a lesser extent among full-time working women, in the decade of economic growth which ended with the recession of 2008. PP was also associated with some compression in the lower half of the wage distribution for women. The effects were predominantly associated with a broad measure of PP that included bonuses. However, these effects were modest, typically not exceeding a 0.05 log points change in log wage differentials over the decade. Moreover there is no indication that PP became increasingly prevalent, as some had predicted, over the decade prior to recession

Do Migrants Lower Workplace Wages?

Using nationally representative workplace data for Britain we identify the partial correlation between workplace wages and the percentage of migrants employed at a workplace. We find wages are lower in workplaces employing a higher percentage of migrants, but only when those migrants are non-EEA migrants. However, the effects are no longer apparent when we condition on the ethnic complexion of employees at the workplace. Instead, the wage penalty is attached to the percentage of non-white employees, a finding that is consistent with employer discrimination on grounds of race, or lower worker bargaining power when employees are ethnically diverse