9,087 research outputs found
Mosaicking with cosmic microwave background interferometers
Measurements of cosmic microwave background (CMB) anisotropies by
interferometers offer several advantages over single-dish observations. The
formalism for analyzing interferometer CMB data is well developed in the
flat-sky approximation, valid for small fields of view. As the area of sky is
increased to obtain finer spectral resolution, this approximation needs to be
relaxed. We extend the formalism for CMB interferometry, including both
temperature and polarization, to mosaics of observations covering arbitrarily
large areas of the sky, with each individual pointing lying within the flat-sky
approximation. We present a method for computing the correlation between
visibilities with arbitrary pointing centers and baselines and illustrate the
effects of sky curvature on the l-space resolution that can be obtained from a
mosaic.Comment: 9 pages; submitted to Ap
Kansas secondary school health services
Dissertation (Ed.D.)--University of Kansas, Education, 1954
A Preliminary Study of the Visual Field in Athletics
If a basketball player sees an area half as large as another player, he has less chance of sizing up the entire situation on the floor at any moment. Likewise, if one player secs less at a given time than he did previously or will in the future, he is probably less effective at that given time. This study attempts first to discover whether or not there is a reason to suspect a measurable relationship between the size of the visual field and successful basketball playing. If there is, obviously a test of visual fields would be advantageous to a coach deciding which inexperienced candidates should be trained. Secondly, this study investigates the effects of fatigue upon the size of the visual field, i.e., does a tired man actually see less? If he does see less, what are the characteristics of the recovery of normal vision? Rather than prepare and conduct an extensive survey immediately, this study was designed to precede a more complete research, to suggest tentative conclusions, and to reveal the difficulties and uncontrollable variations in such work
Characterizing Planetary Orbits and the Trajectories of Light
Exact analytic expressions for planetary orbits and light trajectories in the
Schwarzschild geometry are presented. A new parameter space is used to
characterize all possible planetary orbits. Different regions in this parameter
space can be associated with different characteristics of the orbits. The
boundaries for these regions are clearly defined. Observational data can be
directly associated with points in the regions. A possible extension of these
considerations with an additional parameter for the case of Kerr geometry is
briefly discussed.Comment: 49 pages total with 11 tables and 10 figure
A Lesson in Carefully Managing Resources: A Case Study from an Evaluation of a Music Education Program
Background: A music education program with a goal of enhancing cognitive development of preschool-aged children enrolled in local preschools is evaluated by The Evaluation Center at Western Michigan University. The budget for the evaluation was small, and therefore presented several challenges to the evaluation team. Purpose: Through a case study of a local education program, the authors explore the challenges and possible solutions of evaluating a program within time, budget, data, and political constraints. Setting: The case study of a local music education program is implemented in a medium size Midwestern town. Intervention: The local music education program is a participatory music program for preschool-aged children. The program provides a combination of music classes, performances, and parent education to all participants, with further musical opportunities for interested parents and children. Research Design: The research and data collection portion of the evaluation was conducted using participatory strategies, and involved a management oriented approach. Data Collection and Analysis: Data collection for years one and two (process) consisted of primarily qualitative methods, triangulated by exploratory quantitative data collection. Data collection for year three (impact) will consist of primarily quantitative methods, triangulated with results from the qualitative analysis done in years one and two. Findings: Four factors, time, data, budget, and political, constrain the design and conduct of a local evaluation, yet, evaluators may implement multiple solutions that lessen the effect of the constraints on the evaluation.Keywords: evaluation, evaluation constraints, RealWorld Evaluatio
Hyper-efficient model-independent Bayesian method for the analysis of pulsar timing data
A new model independent method is presented for the analysis of pulsar timing
data and the estimation of the spectral properties of an isotropic
gravitational wave background (GWB). We show that by rephrasing the likelihood
we are able to eliminate the most costly aspects of computation normally
associated with this type of data analysis. When applied to the International
Pulsar Timing Array Mock Data Challenge data sets this results in speedups of
approximately 2 to 3 orders of magnitude compared to established methods. We
present three applications of the new likelihood. In the low signal to noise
regime we sample directly from the power spectrum coefficients of the GWB
signal realization. In the high signal to noise regime, where the data can
support a large number of coefficients, we sample from the joint probability
density of the power spectrum coefficients for the individual pulsars and the
GWB signal realization. Critically in both these cases we need make no
assumptions about the form of the power spectrum of the GWB, or the individual
pulsars. Finally we present a method for characterizing the spatial correlation
between pulsars on the sky, making no assumptions about the form of that
correlation, and therefore providing the only truly general Bayesian method of
confirming a GWB detection from pulsar timing data.Comment: 9 pages, 4 figure
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