Cool Core Bias in Sunyaev-Zel'dovich Galaxy Cluster Surveys

Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01% - 10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~ 6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees.Comment: 8 pages, 4 figures, accepted to Ap

Standing on the Shoulders of Previous Neuroscience Research

The author briefly discusses the field of neuroscience research, including what challenges modern-day researchers face

Synthesis and C−C Coupling Reactivity of a Dinuclear Ni^I−Ni^I Complex Supported by a Terphenyl Diphosphine

Mono- and bimetallic complexes of nickel supported by a terphenyl diphosphine have been synthesized. The reported complexes show diverse metal−arene interactions in the solid state. Reactions of an o,o′-biphenyldiyl dinickel complex with CO and dichloroalkanes lead to fluorene derivatives, indicating the formation of carbon−carbon bonds at a bimetallic moiety

Enhanced tactical symbology for command and control of ground forces

This thesis is directed at the design and evaluation of "enhanced" ground-force map symbology. Enhanced symbology differs from conventional in that enhanced symbols quantify and clarify information on particular units such as combat effectiveness, personnel strength, equipment density and logistics readiness, A variety of design properties compiled from several sources that should be considered when fashioning a new military symbol group is discussed with special emphasis on reducing the negative effects of clutter. A suggested symbol set is developed for support of tactical decision-making and for display on computer graphics systems. The performance of this symbology is then evaluated through an experiment designed to compare the process of quickly and easily solving tactical problems with the enhanced decision aids versus the conventional. An analysis of the experiment results indicates that a commander can reach a tactical decision faster using enhanced symbology.http://archive.org/details/enhancedtactical00hawrCaptain, United States ArmyCaptain, United States Marine CorpsApproved for public release; distribution is unlimited

The effectiveness of the federal funds rate as the U.S. monetary policy tool before, during and after the great recession

The effectiveness of the Federal Reserve’s policy of quantitative easing via large-scale asset purchase programs has been studied extensively. This paper distinguishes itself by examining the effectiveness of the federal funds rate as the U.S. monetary policy tool before, during and after the Great Recession of 2007-09. The zero lower bound came into play one year into the Great Recession, having dropped 425 basis points from the cycle peak. We begin by evaluating using the Wald test for Granger causality and the Johansen test for cointegration presence whether or not the changes in the federal funds rate affected the term structure of Treasury securities. Given that equity markets are sensitive to changes in interest rates, we next examine the impact of the federal funds rate changes on the level and volatility of the U.S. stock market. Our analysis reveals that the Fed policy of lowering the federal funds rate during the Great Recession was effective, resulting in changes in the Treasury term structure during but not after the Great Recession. Additionally, the Fed’s policy actions influenced the stock market and its volatility during the Great Recession only.peer-reviewe

The Roles and Responsibilities of Graduate Education Deans: Mapping Current and Future Job Challenges

Graduate education is changing, driven by social issues, expectations, and technology. Leaders of graduate education play important roles in understanding these changes. The purpose for conducting the study was to profile the professional setting of the graduate dean, exploring the roles, responsibilities, and challenges of the position. Using a research-team developed instrument, graduate education leaders were surveyed. Descriptive findings of the study included the nomenclature of titles who held full time appointments and had an academic background in the liberal arts. The roles and responsibilities of these respondents were reported as a group and separated by research and comprehensive universities