A note on the Lee-Yang singularity coupled to 2d quantum gravity

We show how to obtain the critical exponent of magnetization in the Lee-Yang edge singularity model coupled to two-dimensional quantum gravity

Defining an Agency: Animals, Fire, and the U.S. Forest Service

Today, the United States Forest Service has established itself as an enduring authority on federal lands management. However, in 1905 when the federal government established the agency, its fate was far from secure. Prior to 1905, people living in the West had unchecked access to public land resources and many disapproved of an expansion of federal power. It was the issue of forest fire fighting that gained public support for the agency, and animals, in large part, helped them succeed. Horses and mules were used for transportation, scouting missions and trail building before adequate technology existed. Every ranger was required to own a horse and these animals provided uniformity and respectability to the rangers who were at times disrespected. Additionally, rangers sent carrier pigeons to quickly communicate the location of fires. These animals helped fight forest fires when success for the agency was crucial. As technology gradually proved these domesticated animals obsolete, animals were used in a new method. The Forest Service used the public’s love of animals to gain lasting support for their agency and engage the public in preventing fires themselves, as evidenced by the use of Bambi and Smokey Bear. Throughout the first fifty years of the USFS, the role of animals shifted from an active fighting role to a prevention and educational strategy for the public. Using various American newspapers, periodicals and government documents, I demonstrate that animals played a key role in the USFS’ efficiency, visibility, professionalization, and public engagement and increased respect for the agency in order to create a lasting reputable agency that we still have today

Conditioning of Leverage Scores and Computation by QR Decomposition

The leverage scores of a full-column rank matrix A are the squared row norms of any orthonormal basis for range(A). We show that corresponding leverage scores of two matrices A and A + \Delta A are close in the relative sense, if they have large magnitude and if all principal angles between the column spaces of A and A + \Delta A are small. We also show three classes of bounds that are based on perturbation results of QR decompositions. They demonstrate that relative differences between individual leverage scores strongly depend on the particular type of perturbation \Delta A. The bounds imply that the relative accuracy of an individual leverage score depends on: its magnitude and the two-norm condition of A, if \Delta A is a general perturbation; the two-norm condition number of A, if \Delta A is a perturbation with the same norm-wise row-scaling as A; (to first order) neither condition number nor leverage score magnitude, if \Delta A is a component-wise row-scaled perturbation. Numerical experiments confirm the qualitative and quantitative accuracy of our bounds.Comment: This version has been accepted to SIMAX but has not yet gone through copy editin

Geographic Variation of Cirques on Iceland: Factors Influencing Cirque Morphology

Cirques are one of the most common glacial landforms in alpine settings. They also provide important paleoclimate information (e.g. Meierding 1984; Evans 2006). The purpose of this study is to fill in gaps in the climate record of Iceland by conducting a quantitative analysis of cirques in three regions in Iceland: Tröllaskagi, the East Fjords, and Vestfirðir. Iceland, located in the center of the North Atlantic Ocean, contains many small glaciers, in addition to large ice caps. The glaciers on Iceland are particularly sensitive to variations in oceanic and atmospheric circulation (Andresen et al. 2005; Geirsdóttir et al., 2009; Ólafsdóttir et al. 2010). Iceland thus provides an excellent case study to examine factors influencing glacial landforms such as cirques. (excerpt

Translation Revision: Correlating Revision Procedure and Error Detection

This article reports on an empirical study on translation revision. With the aim of investigating the possible link between revision procedure and quality, the research correlates an indicator of quality, error detection, with revision procedure. Error detection and revision procedure were studied drawing on a convergent parallel mixed-methods research design involving three different sources of data. Nine subjects performed a revision task and thus produced text data; their activities on the computer screen were captured and saved as video fi les; and retrospective interviews were conducted with the revisers upon completion of the task. Results show that the highest error detection scores were linked with a variety of revision procedures, but with one common denominator: the target text was consistently the point of departure. Revisers with high error detection scores thus engaged in various different revision procedures, but their focus of attention in the initial operations was the translation rather than the source text in all cases. Conversely, the revisers whose initial attention was directed towards the source text received the lowest error detection scores in the revision task

Self-organized stable pacemakers near the onset of birhythmicity

General amplitude equations for reaction-diffusion systems near to the soft onset of birhythmicity described by a supercritical pitchfork-Hopf bifurcation are derived. Using these equations and applying singular perturbation theory, we show that stable autonomous pacemakers represent a generic kind of spatiotemporal patterns in such systems. This is verified by numerical simulations, which also show the existence of breathing and swinging pacemaker solutions. The drift of self-organized pacemakers in media with spatial parameter gradients is analytically and numerically investigated.Comment: 4 pages, 4 figure