5,788 research outputs found
Will Employers Want Aging Boomers?
Explores the status quo of older workers; why baby boomers are likely to work longer; and how changes in needed skills, the characteristics of older workers, and labor force growth will affect demand for older workers. Includes policy recommendations
Learning Styles of Farmers and Others Involved with the Maine Potato Industry
The article reports on the learning preferences of Maine Potato Industry representatives. Using the Gregorc Mind Styles™ approach to examine learning styles, we categorized potato farmers, university/government employees, allied industry personnel, and others involved in the potato industry into four learning styles: Concrete Sequential, Concrete Random, Abstract Sequential, and Abstract Random. The plurality of potato farmers were Concrete Sequential, while the plurality of university/government employees and allied industry personnel were Abstract Random. The difference in learning styles of the deliverers and the recipients of the information can result in poor communication and a less than optimum learning environment
The TRENDS High-Contrast Imaging Survey. VI. Discovery of a Mass, Age, and Metallicity Benchmark Brown Dwarf
The mass and age of substellar objects are degenerate parameters leaving the
evolutionary state of brown dwarfs ambiguous without additional information.
Theoretical models are normally used to help distinguish between old, massive
brown dwarfs and young, low mass brown dwarfs but these models have yet to be
properly calibrated. We have carried out an infrared high-contrast imaging
program with the goal of detecting substellar objects as companions to nearby
stars to help break degeneracies in inferred physical properties such as mass,
age, and composition. Rather than using imaging observations alone, our targets
are pre-selected based on the existence of dynamical accelerations informed
from years of stellar radial velocity (RV) measurements. In this paper, we
present the discovery of a rare benchmark brown dwarf orbiting the nearby
( pc), solar-type (G9V) star HD 4747 ([Fe/H]=)
with a projected separation of only AU (
0.6"). Precise Doppler measurements taken over 18 years reveal the companion's
orbit and allow us to place strong constraints on its mass using dynamics (). Relative photometry (,
, ) indicates that HD 4747 B is
most-likely a late-type L-dwarf and, if near the L/T transition, an intriguing
source for studying cloud physics, variability, and polarization. We estimate a
model-dependent mass of for an age of
Gyr based on gyrochronology. Combining astrometric measurements with RV data,
we calculate the companion dynamical mass () and orbit
() directly. As a new mass, age, and metallicity benchmark, HD
4747 B will serve as a laboratory for precision astrophysics to test
theoretical models that describe the emergent radiation of brown dwarfs.Comment: Accepted to Ap
Predicting the effects of unmodeled dynamics on an aircraft flight control system design using eigenspace assignment
When using eigenspace assignment to design an aircraft flight control system, one must first develop a model of the plant. Certain questions arise when creating this model as to which dynamics of the plant need to be included in the model and which dynamics can be left out or approximated. The answers to these questions are important because a poor choice can lead to closed-loop dynamics that are unpredicted by the design model. To alleviate this problem, a method has been developed for predicting the effect of not including certain dynamics in the design model on the final closed-loop eigenspace. This development provides insight as to which characteristics of unmodeled dynamics will ultimately affect the closed-loop rigid-body dynamics. What results from this insight is a guide for eigenstructure control law designers to aid them in determining which dynamics need or do not need to be included and a new way to include these dynamics in the flight control system design model to achieve a required accuracy in the closed-loop rigid-body dynamics. The method is illustrated for a lateral-directional flight control system design using eigenspace assignment for the NASA High Alpha Research Vehicle (HARV)
Generalized software requirements to access thesauri and classification schemes for user-based image collections
This paper describes proposed schemes for describing and indexing two image collections and equirements for the software that would give the end-user access to thesaurus terms and a graphical display of the faceted classification structures of indexing records. Editorial cartoons comprise one collection, dance videos the other
The Impact of PRRS on the Pig Cost of Production
Porcine Reproductive and Respiratory Syndrome (PRRS) has had a significant impact on the profitability of swine production. As a means to quantify the financial impact of PRRS to the U.S. swine industry, a study was conducted. This study utilized case studies and a Delphi survey to identify the various impacts PRRS has on farms. Results suggest that impacts to individual farms vary greatly but aggregated data for approximately 100 million market swine being sold each year in the U.S., estimates PRRS adds somewhere between 7.62 to the cost per head sold
A Search for Exozodiacal Clouds with Kepler
Planets embedded within dust disks may drive the formation of large scale
clumpy dust structures by trapping dust into resonant orbits. Detection and
subsequent modeling of the dust structures would help constrain the mass and
orbit of the planet and the disk architecture, give clues to the history of the
planetary system, and provide a statistical estimate of disk asymmetry for
future exoEarth-imaging missions. Here we present the first search for these
resonant structures in the inner regions of planetary systems by analyzing the
light curves of hot Jupiter planetary candidates identified by the Kepler
mission. We detect only one candidate disk structure associated with KOI 838.01
at the 3-sigma confidence level, but subsequent radial velocity measurements
reveal that KOI 838.01 is a grazing eclipsing binary and the candidate disk
structure is a false positive. Using our null result, we place an upper limit
on the frequency of dense exozodi structures created by hot Jupiters. We find
that at the 90% confidence level, less than 21% of Kepler hot Jupiters create
resonant dust clumps that lead and trail the planet by ~90 degrees with optical
depths >~5*10^-6, which corresponds to the resonant structure expected for a
lone hot Jupiter perturbing a dynamically cold dust disk 50 times as dense as
the zodiacal cloud.Comment: 22 pages, 6 figures, Accepted for publication in Ap
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