Measuring eccentricity in binary black-hole initial data

Initial data for evolving black-hole binaries can be constructed via many techniques, and can represent a wide range of physical scenarios. However, because of the way that different schemes parameterize the physical aspects of a configuration, it is not alway clear what a given set of initial data actually represents. This is especially important for quasiequilibrium data constructed using the conformal thin-sandwich approach. Most initial-data studies have focused on identifying data sets that represent binaries in quasi-circular orbits. In this paper, we consider initial-data sets representing equal-mass black holes binaries in eccentric orbits. We will show that effective-potential techniques can be used to calibrate initial data for black-hole binaries in eccentric orbits. We will also examine several different approaches, including post-Newtonian diagnostics, for measuring the eccentricity of an orbit. Finally, we propose the use of the ``Komar-mass difference'' as a useful, invariant means of parameterizing the eccentricity of relativistic orbits.Comment: 12 pages, 11 figures, submitted to Physical Review D, revtex

Simple Computational Methods for Measuring the Difference of Empirical Distributions: Application to Internal and External Scope Tests in Contingent Valuation

This paper develops a statistically unbiased and simple method for measuring the difference of independent empirical distributions estimated by bootstrapping or other simulation approaches. This complete combinatorial method is compared with other unbiased and biased methods that have been suggested in the literature, first in Monte Carlo simulations and then in a field test of external and internal scope testing in contingent valuation. Tradeoffs between methods are discussed. When the empirical distributions are not independent a straightforward difference test is suggested.Research Methods/ Statistical Methods,

Building top management muscle in a slow growth environment: How different is better at Greyhound Financial Corporation

The turbulence experienced in the 1980s in the U.S. business environment has led to something of a motivational crisis among corporate managers. Increased competition, budget constraints, and changing demographics are forcing companies into adopting strategies geared toward downsizing and flatter organizational structures. While corporate America probably has begun to accept its leaner profile, it has not yet successfully addressed the issue of how to keep the best managerial talent tuned in and turned on in an era of dwindling resources. This article describes and assesses one corporation\u27s efforts to maintain top-managerial motivation through a unique form of job swapping called the Muscle Building program at Greyhound Financial Corporation in Phoenix, Arizona. Muscle building. a top-management job rotation program, helps prevent career gridlock, fosters management diversity, and provides for top-management succession. Hidden costs and benefits of the program and issues concerning its implementation are discussed

Approximate Killing Vectors on S^2

We present a new method for computing the best approximation to a Killing vector on closed 2-surfaces that are topologically S^2. When solutions of Killing's equation do not exist, this method is shown to yield results superior to those produced by existing methods. In addition, this method appears to provide a new tool for studying the horizon geometry of distorted black holes.Comment: 4 pages, 3 figures, submitted to Physical Review D, revtex

Borgs in the Org? Organizational Decision Making and Technology

Data warehousing and the development of the World Wide Web both augment information gathering (search) processes in individual decision making by increasing the availability of required information. Imagine, for example, that one wanted to buy new golf clubs. Thirty years ago, the cost of information gathering would likely have limited an individual\u27s search process to geographically proximal vendors and the golf clubs they stocked. Today, a prospective purchaser can log onto the World Wide Web to find out what types of golf clubs are available anywhere; consult databases, chat rooms, and bulletin boards (e.g., epinions.com) to gather product information and user opinions; and compare prices across vendors around the world

Microgravity: A Teacher's Guide With Activities in Science, Mathematics, and Technology

The purpose of this curriculum supplement guide is to define and explain microgravity and show how microgravity can help us learn about the phenomena of our world. The front section of the guide is designed to provide teachers of science, mathematics, and technology at many levels with a foundation in microgravity science and applications. It begins with background information for the teacher on what microgravity is and how it is created. This is followed with information on the domains of microgravity science research; biotechnology, combustion science, fluid physics, fundamental physics, materials science, and microgravity research geared toward exploration. The background section concludes with a history of microgravity research and the expectations microgravity scientists have for research on the International Space Station. Finally, the guide concludes with a suggested reading list, NASA educational resources including electronic resources, and an evaluation questionnaire

Leaving Nothing to Chance: Modeling the Proactive Structuration of a New Technology

Adaptive structuration theory (AST, DeSanctis and Poole 1994) describes how people come to understand and use a technology. In this paper we develop the idea of proactive structuration--how social networking can be proactively managed in order to speed the comprehensive adaptation of a technology within a community of users. We examine two facets of proactive structuration--formal institutionalization of a community of practice and socialization of users--and stochastically model the impact of proactive structuration on comprehensive adaptation latency. Implications for the effective management of new technology adoption are discussed.

Experimental measurements of the ground cloud growth during the 11 February 1974, Titan-Centaur launch at Kennedy Space Center

The Titan-Centaur was launched from Kennedy Space Center on February 11, 1974 at 0948 eastern daylight time. Ground level effluent measurements were obtained from the solid rocket motors for comparison with NASA diffusion models for predicting effluent ground level concentrations and cloud behavior. The results obtained provide a basis for an evaluation of such key model inputs such as cloud rise rate, stabilization altitude, crosswind growth, volume expansion, and cloud trajectory. Ground level effluent measurements were limited because of changing meteorological conditions, incorrect instrument location, and operational problems. Based on the measurement results, operational changes are defined. Photographs of the ground exhaust clouds are shown. The chemical composition of the exhaust gases was analyzed and is given