Self-scaled barriers for irreducible symmetric cones

Self-scaled barrier functions are fundamental objects in the theory of interior-point methods for linear optimization over symmetric cones, of which linear and semidefinite programming are special cases. We are classifying all self-scaled barriers over irreducible symmetric cones and show that these functions are merely homothetic transformations of the universal barrier function. Together with a decomposition theorem for self-scaled barriers this concludes the algebraic classification theory of these functions. After introducing the reader to the concepts relevant to the problem and tracing the history of the subject, we start by deriving our result from first principles in the important special case of semidefinite programming. We then generalise these arguments to irreducible symmetric cones by invoking results from the theory of Euclidean Jordan algebras.Comment: 12 page

MS-226: Nineteenth Century Pennsylvania Trade Cards

This collection contains 80 nineteenth century trade cards from businesses primarily in Philadelphia (six are from other Pennsylvania location) as well as two decorative images and one three- dimensional square map of Central Europe in German. The cards advertise for a variety of goods and services, including clothing, groceries, beauty and health products, printers, plumbers, jewelers, florists, and more. Many of the cards depict cherubic children, fashionable men and women, prudent consumers using the products advertised, fine art, and include poems, promotions, and manufacturer guarantees. These cards may be of interest to anyone studying methods of advertisement and marketing, graphic design, business history, pharmaceutical history, consumer habits, 19th century fashion and customs, as well as other aspects of Pennsylvania or American social and cultural history. Special Collections and College Archives Finding Aids are discovery tools used to describe and provide access to our holdings. Finding aids include historical and biographical information about each collection in addition to inventories of their content. More information about our collections can be found on our website http://www.gettysburg.edu/special_collections/collections/.https://cupola.gettysburg.edu/findingaidsall/1194/thumbnail.jp

The effect of thermal diffusion on the formation of interface resistance on oxide-coated cathodes.

Thesis (M.A.)--Boston UniversityThe goal of this investigation is to determine many of the factors which contribute to cathode interface resistance formation in a commercial type twin triode and to analyze these factors quantitatively by well known chemical and physical methods, However, since the vacuum tube represents such a complex system it is necessary to introduce this problem by reference to early history and many of the parameters associated with vacuum tube manufacture. With reference to historical introduction, the electron theory of metals, with special emphasis on the role which work function plays, is discussed. [TRUNCATED

Correlates of substitution rate variation in mammalian protein-coding sequences

BACKGROUND: Rates of molecular evolution in different lineages can vary widely, and some of this variation might be predictable from aspects of species' biology. Investigating such predictable rate variation can help us to understand the causes of molecular evolution, and could also help to improve molecular dating methods. Here we present a comprehensive study of the life history correlates of substitution rate variation across the mammals, comparing results for mitochondrial and nuclear loci, and for synonymous and non-synonymous sites. We use phylogenetic comparative methods, refined to take into account the special nature of substitution rate data. Particular attention is paid to the widespread correlations between the components of mammalian life history, which can complicate the interpretation of results. RESULTS: We find that mitochondrial synonymous substitution rates, estimated from the 9 longest mitochondrial genes, show strong negative correlations with body mass and with maximum recorded lifespan. But lifespan is the sole variable to remain after multiple regression and model simplification. Nuclear synonymous substitution rates, estimated from 6 genes, show strong negative correlations with body mass and generation time, and a strong positive correlation with fecundity. In contrast to the mitochondrial results, the same trends are evident in rates of nonsynonymous substitution. CONCLUSION: A substantial proportion of variation in mammalian substitution rates can be explained by aspects of their life history, implying that molecular and life history evolution are closely interlinked in this group. The strength and consistency of the nuclear body mass effect suggests that molecular dating studies may have been systematically misled, but also that methods could be improved by incorporating the finding as a priori information. Mitochondrial synonymous rates also show the body mass effect, but for apparently quite different reasons, and the strength of the relationship with maximum lifespan provides support for the hypothesis that mtDNA damage is causally linked to aging

The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys

Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of Active Galactic Nuclei (AGN) ranging from radio to hard X-ray wavelengths. We then describe the most commonly used methods to find these sources, including optical/UV, radio, infrared and X-ray emission and optical emission lines. We then describe the main observational properties of the obscured and unobscured AGN population. Finally, we summarize the cosmic history of black hole accretion, i.e., when in the history of the Universe supermassive black holes were getting most of their mass. We finish with a summary of open questions and a description of planned and future observatories that are going to help answer them.Comment: 33 pages, 20 figures, review paper accepted for the Advances in Astronomy Special Issue "Seeking for the Leading Actor on the Cosmic Stage: Galaxies versus Supermassive Black Holes

Simulation techniques for cosmological simulations

Modern cosmological observations allow us to study in great detail the evolution and history of the large scale structure hierarchy. The fundamental problem of accurate constraints on the cosmological parameters, within a given cosmological model, requires precise modelling of the observed structure. In this paper we briefly review the current most effective techniques of large scale structure simulations, emphasising both their advantages and shortcomings. Starting with basics of the direct N-body simulations appropriate to modelling cold dark matter evolution, we then discuss the direct-sum technique GRAPE, particle-mesh (PM) and hybrid methods, combining the PM and the tree algorithms. Simulations of baryonic matter in the Universe often use hydrodynamic codes based on both particle methods that discretise mass, and grid-based methods. We briefly describe Eulerian grid methods, and also some variants of Lagrangian smoothed particle hydrodynamics (SPH) methods.Comment: 42 pages, 16 figures, accepted for publication in Space Science Reviews, special issue "Clusters of galaxies: beyond the thermal view", Editor J.S. Kaastra, Chapter 12; work done by an international team at the International Space Science Institute (ISSI), Bern, organised by J.S. Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke

Statistical Software for State Space Methods

In this paper we review the state space approach to time series analysis and establish the notation that is adopted in this special volume of the Journal of Statistical Software. We first provide some background on the history of state space methods for the analysis of time series. This is followed by a concise overview of linear Gaussian state space analysis including the modelling framework and appropriate estimation methods. We discuss the important class of unobserved component models which incorporate a trend, a seasonal, a cycle, and fixed explanatory and intervention variables for the univariate and multivariate analysis of time series. We continue the discussion by presenting methods for the computation of different estimates for the unobserved state vector: filtering, prediction, and smoothing. Estimation approaches for the other parameters in the model are also considered. Next, we discuss how the estimation procedures can be used for constructing confidence intervals, detecting outlier observations and structural breaks, and testing model assumptions of residual independence, homoscedasticity, and normality. We then show how ARIMA and ARIMA components models fit in the state space framework to time series analysis. We also provide a basic introduction for non-Gaussian state space models. Finally, we present an overview of the software tools currently available for the analysis of time series with state space methods as they are discussed in the other contributions to this special volume.

Voices from D-Day, June 6, 1944

Seventy years on from D-Day, we still marvel at the stoic heroism of the men who contributed to the success of what remains the greatest amphibious invasion in the history of warfare. The Normandy campaign would, in one way or another, prove a pivotal moment in the ongoing world war. A disaster in the campaign to liberate France would set back Allied hopes for crushing Nazism in Western Europe. It would also fray the alliance with the Soviet Union that was essential to defeating Hitler’s forces. By contrast, success would mark not just the end of the beginning of the conflict, but the beginning of the end. There are as many Normandy campaign stories, from both sides, as there are participants. But absent some formal way of collecting them, those stories would disappear with the generation that made this history. That is where oral history comes in. Since the early 1990s, Gettysburg College has done its share to create an archive of World War II memories, covering the gamut of life experience of a generation that grew to maturity during the Great Depression and World War II. Launched in a Historical Methods course in 1991, and continuing into the present day, the World War II oral history project has collected nearly 700 oral histories from the home and battle fronts and places in between. Recordings and transcriptions of each of these interviews are available in Special Collections at Musselman Library. At some point, if resources are sufficient, they will be digitized and available online. [excerpt]https://cupola.gettysburg.edu/libexhibits/1003/thumbnail.jp