10,033 research outputs found
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
Thunder in the Distance: The Emerging Policy Debate Over Wildlife Contraception
Wildlife contraception is only now emerging as a wildlife policy issue It will emerge into a sociopolitical environment that is already polarized from a clash of ideologies. The wildlife conservation/hunting community strives to preserve the status quo while animal welfare and animal rights activists struggle to change wildlife management philosophy and practice to conform to their respective beliefs. Recent professional and popular literature reveal at least four major areas of conflict: (1) anti-management sentiment, (2) anti-hunting sentiment, (3) animal rights sentiment, and (4) animal welfare sentiment. Wildlife managers anticipate that the conflict over the use of contraceptives will involve value and belief conflicts between traditional wildlife management and animal rights proponents. We believe instead that the primary conflicts will revolve around pragmatic issues such as when, where, and in which circumstances managers will LISP the contraceptive tool. In this context, wildlife contraception will be regarded as a mixed bag. Given the nature and potential polarity of the wildlife contraception issue, wildlife agencies will have to behave proactively by projecting themselves into their future. Currently, wildlife agencies respond to many policy challenges reactively and defensively in an attempt to preserve their past. If a productive compromise can be reached over the issue of if, how, when, and where to use wildlife contraception, the wildlife policy decision process must be visionary, wise, bold, accessible, adaptable, and, most of all, fair
- …