3,082 research outputs found
Environmental Messages in Boating Magazines: A Content Analysis of Recreational Power Boating Articles
This paper presents the results of a study analyzing the editorial content of consumer power boating magazines for messages of environmental responsibility. It presents evidence of a cause and effect relationship between recreational power boating and damage to the marine environment, and cites arguments that power boating in its currently popular form, involving high speeds and heavy fuel consumption, is inherently unfriendly to the environment. The paper describes a chain of influence through which boat manufacturers, in their role as advertisers, influence the editorial content of consumer boating magazines through the tactics of marketing public relations. A hypothesis is developed which states that publishers\u27 commercial interests behoove them to publish editorial material generally supportive of their advertisers, hence promoting consumer behaviors that damage the environment through profligacy of fuel consumption leading to excessive engine emissions. Three magazines are selected for analysis, based on their high levels of influence and visibility within the consumer boating market: Boating, Motor Boating & Sailing, and Power & Motoryacht. These magazines maintain the largest circulation figures of all North American consumer power boating magazines, with a combine monthly circulation totaling more than one half million issues and a substantial pass-along readership. The hypotheses is tested using methods of content analysis. Separate tests are employed to analyze five different types of editorial content: textual content of boat test feature articles; photographic content of boat test feature articles; topical content of how to articles on two specific subjects (boat handling, and maintenance); topical content and slant of opinion columns; and topical content of feature articles explicitly addressing environmental issues. Test results fail to support the hypothesis, suggesting that special-interest consumer publishing in the recreational power boating niche maintains a degree of editorial independence from advertisers, and that environmental topics are treated in a reasonably balanced manner
Image synthesis for SAR system, calibration and processor design
The Point Scattering Method of simulating radar imagery rigorously models all aspects of the imaging radar phenomena. Its computational algorithms operate on a symbolic representation of the terrain test site to calculate such parameters as range, angle of incidence, resolution cell size, etc. Empirical backscatter data and elevation data are utilized to model the terrain. Additionally, the important geometrical/propagation effects such as shadow, foreshortening, layover, and local angle of incidence are rigorously treated. Applications of radar image simulation to a proposed calibrated SAR system are highlighted: soil moisture detection and vegetation discrimination
Adaptive filtering of radar images for autofocus applications
Autofocus techniques are being designed at the Jet Propulsion Laboratory to automatically choose the filter parameters (i.e., the focus) for the digital synthetic aperture radar correlator; currently, processing relies upon interaction with a human operator who uses his subjective assessment of the quality of the processed SAR data. Algorithms were devised applying image cross-correlation to aid in the choice of filter parameters, but this method also has its drawbacks in that the cross-correlation result may not be readily interpretable. Enhanced performance of the cross-correlation techniques of JPL was hypothesized given that the images to be cross-correlated were first filtered to improve the signal-to-noise ratio for the pair of scenes. The results of experiments are described and images are shown
Mixed Dark Matter from Axino Distribution
We study the possibility of mixed dark matter obtained through the phase
space distribution of a single particle. An example is offered in the context
of SUSY models with a Peccei-Quinn symmetry. Axinos in the 100 keV range can
naturally have both thermal and non-thermal components. The latter one arises
from the lightest neutralino decays and derelativizes at z ~ 10^4.Comment: Figures added, references fixed. Version accepted for publication on
Phys. Rev. D. LaTeX. 9 pages, 3 figures, uses epsfig.st
Simulation of orbital radar images
Many of the questions that arise concerning the operating parameters
for spaceborne synthetic aperture imaging radar systems can
be addressed in a cost-effective manner by using simulation techniques.
This can include use of airborne images, Seasat images, and computer
simulation. The first computer simulation of spaceborne radar imagery
has been analyzed for system definition studies. Analysis of the
simulation indicates that incidence angles as small as 30° are useful
for general terrain geomorphologic analysis
Stellar luminosity functions of rich star clusters in the Large Magellanic Cloud
We show the results of deep V and I HST photometry of 6 rich star clusters in
the Large Magellanic Cloud with different ages and metallicities. The number of
stars with measured magnitudes in each cluster varies from about 3000 to 10000.
We build stellar density and surface brightness profiles for the clusters and
extract half-light radii and other structural parameters for each. We also
obtain luminosity functions, Phi (Mv), down to Mv ~ 6 (m/msun > 0.6), and
investigate their dependence with distance from the cluster centre well beyond
their half-light radius. In all clusters we find a systematic increase in the
luminosity function slope with radial distance from the centre. Among the
clusters displaying significant mass segregation are the two youngest in the
sample: NGC 1805 and NGC 1818. For these two clusters we obtain present-day
mass functions. The NGC 1818 mass function is in excellent agreement with that
derived by other authors, also using HST data. They young cluster mass function
slopes differ, that of NCG 1805 being systematically steeper than NGC 1818.
Since these are very young stellar systems (age < 40 Myrs), these variations
may reflect the initial conditions rather than evolution due to internal
dynamics.Comment: 10 pages, 24 figure
Sleep, circadian rhythms, and the pathogenesis of Alzheimer Disease
Disturbances in the sleep–wake cycle and circadian rhythms are common symptoms of Alzheimer Disease (AD), and they have generally been considered as late consequences of the neurodegenerative processes. Recent evidence demonstrates that sleep–wake and circadian disruption often occur early in the course of the disease and may even precede the development of cognitive symptoms. Furthermore, the sleep–wake cycle appears to regulate levels of the pathogenic amyloid-beta peptide in the brain, and manipulating sleep can influence AD-related pathology in mouse models via multiple mechanisms. Finally, the circadian clock system, which controls the sleep–wake cycle and other diurnal oscillations in mice and humans, may also have a role in the neurodegenerative process. In this review, we examine the current literature related to the mechanisms by which sleep and circadian rhythms might impact AD pathogenesis, and we discuss potential therapeutic strategies targeting these systems for the prevention of AD
Cronbach’s Alpha Under Insufficient Effort Responding: An Analytic Approach
Surveys commonly suffer from insufficient effort responding (IER). If not accounted for, IER can cause biases and lead to false conclusions. In particular, Cronbach’s alpha has been empirically observed to either deflate or inflate due to IER. This paper will elucidate how IER impacts Cronbach’s alpha in a variety of situations. Previous results concerning internal consistency under mixture models are extended to obtain a characterization of Cronbach’s alpha in terms of item validities, average variances, and average covariances. The characterization is then applied to contaminating distributions representing various types of IER. The discussion will provide commentary on previous simulation-based investigations, confirming some previous hypotheses for the common types of IER, but also revealing possibilities from newly considered responding patterns. Specifically, it is possible that the bias can change from negative to positive (and vice versa) as the proportion of contamination increases
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