Entry letter from a publisher 1969: Part 20

Entry letters for the Booker Prize from publisher

Defoe the journalist

Thesis (M.A.)--Boston Universit

Embedding high-level quantum mechanical approaches within linear-scaling density functional theory

Advances in computational methods in recent decades have significantly expanded the range of problems in condensed matter physics that can be tackled from first principles. Linear-scaling density functional theory methods enable quantum mechanical calculations to be performed on systems containing tens of thousands of atoms, with modern approaches capable of reproducing the accuracy of plane wave DFT approaches. This opens up the possibility of treating highly complex molecular systems such as doped organic molecular crystals that require the dopant molecule to be contained within a large periodic structure. One example of such a system is pentacene in p-terphenyl, a system that finds use as a room-temperature maser. Understanding the maser mechanism requires both a highly accurate description of the pentacene molecule and a computationally efficient approach that can correctly capture the impact of the p-terphenyl host on the active pentacene subsystem. Quantum embedding allows an accurate but expensive hybrid functional to be embedded within a cheaper semi-local functional, for maximum combination of accuracy and efficiency in a DFT-in-DFT framework. In this dissertation we consider the implementation of embedded mean-field theory (EMFT) in the linear-scaling DFT software package ONETEP, enabling hybrid functionals to be used on selected subsystems within a cheaper DFT environment. This approach is validated for several types of molecular systems, including a crystalline structure containing several thousand atoms, demonstrating the potential of the EMFT approach when combined with linear-scaling and verifying the importance of using a large explicit host environment for accurate calculations.Open Acces

Sense of Agency and the Exhibition of Prosocial Behaviors

The concept of human agency refers to whether or not free will exists. Over the course of history, several philosophers and psychologists have debated this particular topic. As a result, three divergent schools of thought have emerged. One such school posits the doctrine of free will; another articulates the doctrine of determinism. Still another school of thought holds that free will and determinism cannot exist outside of one another. This concept is called compatibilism. Human agency is a necessary contextualization for the scope of the present study. While the debate of human agency has not been fully resolved, this study is concerned with the implications of the belief in agency. Individual belief in free will is referred to as sense of agency. Researchers have indicated that the mere belief in free will or determinism produces cognitive and behavioral effects. A higher belief in free will is correlated with positive cognitive benefits and prosocial behaviors. A diminished sense of agency is correlated with negative cognitive effects and antisocial behaviors. The present study seeks to determine if sense of agency could be primed and subsequently enhanced. If enhanced, the study seeks to determine if a heightened belief in free will leads to an increased exhibition of prosocial behaviors. The present study included the participation of 130 individuals. No significant data was found

Ideals and policies of trade unions in America

This item was digitized by the Internet Archive

Catering for Uncertainty in a Conceptual Rainfall Runoff Model: Model Preparation for Climate Change Impact Assessment and the Application of GLUE using Latin Hypercube Sampling

Changes in Irish climate may pose a number of obstacles for water resource management. There is a need to approach this problem using the catchment as the basic unit of analysis. The application of a lumped conceptual rainfall-runoff model for simulating beyond a baseline calibration set is a major challenge for climate change impact assessment. This is due in no small part to the limitations associated with the use of these models, with uncertainty in model output being associated with model structure and the non-uniqueness of optimised parameter sets. In this paper, HYSIM, an “off-the-shelf” conceptual rainfall runoff model using data on a daily time-step is applied to a suite of catchments throughout Ireland in preparation for use with downscaled climate data. Uncertainties relating to process parameter calibration due to parameter interaction and equifinality are highlighted. In an attempt to improve the reliability of model output the generalised likelihood uncertainty estimation (GLUE) framework is adopted to analyse the uncertainty in model output derived from parametric sources. Traditionally this approach has been applied using Monte Carlo random sampling (MCRS). However, when using an “off-the-shelf” type model, source code may not be available and it may not be feasible to run the model for large MCRS samples without user intervention. In order to make the propagation of uncertainty through the model more efficient, input parameter sets are generated using Latin Hypercube sampling (LHS). A number of acceptable parameter sets are generated and uncertainty bounds are constructed for each time step using the 5th and 95th percentile at each temporal interval. These uncertainty bounds will be used to quantify the uncertainty in simulations carried out beyond the baseline calibration period as they include the error derived from data measurement, model structure, and parameterisation