The Structure of Langevin's Memory Kernel From Lagrangian Dynamics

We obtain the memory kernel of the generalized Langevin equation, describing a particle interacting with longitudinal phonons in a liquid. The kernel is obtained analytically at T=0 Kelvin and numerically at T>0 Kelvin. We find that it shows some non-trivial structural features like negative correlations for some range of time separations. The system is shown to have three characteristic time scales, that control the shape of the kernel, and the transition between quadratic and linear behavior of the mean squared distance (MSD). Although the derivation of the structure in the memory kernel is obtained within a specific dynamical model, the phenomenon is shown to be quite generic.Comment: 8 pages, 5 figures, latex, include europhys.sty and euromacr.te

Comparative efficiency of finite, boundary and hybrid element methods in elastostatics

The comparative computational efficiencies of the finite element (FEM), boundary element (BEM), and hybrid boundary element-finite element (HBFEM) analysis techniques are evaluated for representative bounded domain interior and unbounded domain exterior problems in elastostatics. Computational efficiency is carefully defined in this study as the computer time required to attain a specified level of solution accuracy. The study found the FEM superior to the BEM for the interior problem, while the reverse was true for the exterior problem. The hybrid analysis technique was found to be comparable or superior to both the FEM and BEM for both the interior and exterior problems

Developing a Customized Composite Drought Index for Pakistan

Pakistan experiences frequent and intense agricultural drought, varying spatially and temporally. Prolonged dry conditions often result in failed crop production. Using multiple variables, different components of drought can be captured across a multitude of climatic zones and throughout different seasons. Developing a composite drought index (CDI), specific for each district, will provide a more complete view of agricultural drought and enhance early warning systems

CYCLING AS A POLITICAL ACT: THE FRAMING AND CULTURE THAT CREATE A NEW SOCIAL MOVEMENT

This study analyzes the bicycling community of Lexington, Kentucky. Interviews and participant observation were conducted in order to better understand the structure of Lexington’s cycling community, revealing three prominent groups/types of cyclists: (1) road cyclists, (2) underground/urban cyclists, and (3) commuters. The characteristics of each group are discussed, with particular attention devoted to the underground/urban cyclists, due to their politically-minded culture. Building from prior social movement literature, the unique framing processes of the underground/urban cycling group are analyzed in order to explore the group as a new social movement. Finally, the potential for a broader cycling movement based upon interests common to all cyclists is discussed

A spatio-temporal model for estimating the long-term effects of air pollution on respiratory hospital admissions in Greater London

It has long been known that air pollution is harmful to human health, as many epidemiological studies have been conducted into its effects. Collectively, these studies have investigated both the acute and chronic effects of pollution, with the latter typically based on individual level cohort designs that can be expensive to implement. As a result of the increasing availability of small-area statistics, ecological spatio-temporal study designs are also being used, with which a key statistical problem is allowing for residual spatio-temporal autocorrelation that remains after the covariate effects have been removed. We present a new model for estimating the effects of air pollution on human health, which allows for residual spatio-temporal autocorrelation, and a study into the long-term effects of air pollution on human health in Greater London, England. The individual and joint effects of different pollutants are explored, via the use of single pollutant models and multiple pollutant indices

There Never was a White-Hope Whose Christian Name was Cohen

https://digitalcommons.library.umaine.edu/mmb-vp/6369/thumbnail.jp

We Were There : Anatomy of a Successful Series of Historical Novels for Young People

The study of history has always been an important part of learning. Young people might ask, Why do I need to learn about something I cannot change? When asked Why Study History? William H. McNeill states in Historical Literacy : The Case For History in American Education that the value of historical knowledge obviously justifies teaching and learning about what happened in recent times, for the way things are descends from the way they were yesterday and the day before that (104). Between the years 1955 to 1963 Grossett and Dunlap Publishers introduce a concept that brings personal involvement into historical events by integrating young boys and girls into the action. The We Were There books seem to be developed as lessons in story form to teach young readers how to become the responsible, productive adults. This series is diverse in historical events, such as a cattle drive on the Chisholm Trail and Darwin\u27s discoveries of nature. The authors tend to follow Margaret Mallett\u27s thoughts, in Making Facts Matter, concerning non-fiction in that it helps satisfy the young child\u27s great curiosity about the world of people, plants, animals, inanimate objects and events and feelings about all these things. But knowledge is not just a matter of acquiring facts, it includes coming to understand the significance of the facts (68). The goal of the We Were There book series is to enhance the learning experience by incorporating influential teachers, such as parent figures, employers, neighbors, friends, and famous historical leaders, and by including lessons on foreign Schwartz 2 language, science, religion, ethical conduct, social and political issues, and family relationships. The We Were There series concept and popularity are validated by Scholastic\u27s recently published Dear America Series for girls and the My Name is America Series for boys, in which similar historical events are written in diary and journal form for young readers. Each We Were There book contains a lesson that takes the reader one step closer to understanding what is required when entering into the :final stages of adulthood, such as absorbing events, analyzing those events as to how they influence their lives, then taking what they perceive as the appropriate action. Once a young person has traveled with the We Were There” characters through the series, in its entirety, an evolution will have taken place, within the reader, that encompasses an enhanced understanding of the universe he or she shares with diverse people and events that form life lessons

Electronic properties of the pseudogap system (TaSe4)2I

The room temperature ``metallic'' properties of the quasi-one-dimensional charge density wave system (TaSe4)2I differ markedly from those expected of either a Fermi or a Luttinger Liquid. We discuss evidence for the simplest possible explanation of the observed behavior of (TaSe4)2I in its conducting phase - namely the existence of large quasi-static fluctuations of structural order, which however remain of finite extent above the charge density wave transition temperature. These fluctuations produce a pseudogap in the density of states. We compute the temperature dependence of the optical and DC conductivities of (TaSe4)2I in its conducting phase, the nature of its core hole spectra, and the NMR relaxation rate. Predictions for these quantities are made on the basis of a Lee, Rice and Anderson model. This model represents the simplest theory of a pseudogap, and gives satisfactory agreement with experiment in the cases where comparisons can be made. In contrast, the predictions of a strongly correlated (Luttinger Liquid) model appear to to contradict the data. The chief remaining discrepancy is that the gap appearing in transport quantities is less than that observed in photoemission. We discuss some possibilities for resolving this issue.Comment: 41 pages latex, 11 ps figures, uses IOP macro