2,794 research outputs found
Influence of Technology on Gifted and Talented Elementary School Student Academic Achievement
An applied project submitted in partial fulfillment of the requirements for the degree of Education Specialist at Morehead State University by Karen N. Conn on January 14,1998
Measurement of Dust Optical Properties in Coalsack
We have used FUSE and Voyager observations of dust scattered starlight in the
neighborhood of the Coalsack Nebula to derive the optical constants of the dust
grains. The albedo is consistent with a value of and the phase
function asymmetry factor with a value of throughout the
spectral range from 900 -- 1200 \AA, in agreement with previous determinations
as well as theoretical predictions. We have now observed two regions (Ophiuchus
and Coalsack) with intense diffuse background radiation and in both cases have
found that the emission is due to light from nearby hot stars scattered by a
relatively thin foreground cloud, with negligible contribution from the
background molecular cloud.Comment: Total 19 pages, Figures 9, Accepted for publication in Astrophysical
Journa
GALEX Observations of Diffuse UV Radiation at High Spatial Resolution from the Sandage Nebulosity
Using the GALEX ultraviolet imagers we have observed a region of nebulosity
first identified as starlight scattered by interstellar dust by Sandage (1976).
Apart from airglow and zodiacal emission, we have found a diffuse UV background
of between 500 and 800 \phunit in both the \galex FUV (1350 -- 1750 \AA) and
NUV (1750 -- 2850 \AA). Of this emission, up to 250 \phunit is due to \htwo
fluorescent emission in the FUV band; the remainder is consistent with
scattering from interstellar dust. We have estimated the optical constants to
be in the FUV and in the NUV, implying
highly forward scattering grains, plus an extragalactic contribution of as much
as 150 \phunit. These are the highest spatial resolution observations of the
diffuse UV background to date and show an intrinsic scatter beyond that
expected from instrumental noise alone. Further modeling is required to
understand the nature of this scatter and its implications for the ISM.Comment: Total 20 pages, Figures 9, Accepted for publication in Astrophysical
Journa
A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I)
We present a new approach for identifying the Tip of the Red Giant Branch
(TRGB) which, as we show, works robustly even on sparsely populated targets.
Moreover, the approach is highly adaptable to the available data for the
stellar population under study, with prior information readily incorporable
into the algorithm. The uncertainty in the derived distances is also made
tangible and easily calculable from posterior probability distributions. We
provide an outline of the development of the algorithm and present the results
of tests designed to characterize its capabilities and limitations. We then
apply the new algorithm to three M31 satellites: Andromeda I, Andromeda II and
the fainter Andromeda XXIII, using data from the Pan-Andromeda Archaeological
Survey (PAndAS), and derive their distances as
kpc, kpc and
kpc respectively, where the errors appearing in parentheses are the components
intrinsic to the method, while the larger values give the errors after
accounting for additional sources of error. These results agree well with the
best distance determinations in the literature and provide the smallest
uncertainties to date. This paper is an introduction to the workings and
capabilities of our new approach in its basic form, while a follow-up paper
shall make full use of the method's ability to incorporate priors and use the
resulting algorithm to systematically obtain distances to all of M31's
satellites identifiable in the PAndAS survey area.Comment: 11 pages, 18 figure
Major Substructure in the M31 Outer Halo: the South-West Cloud
We undertake the first detailed analysis of the stellar population and
spatial properties of a diffuse substructure in the outer halo of M31. The
South-West Cloud lies at a projected distance of ~100 kpc from the centre of
M31, and extends for at least ~50 kpc in projection. We use Pan-Andromeda
Archaeological Survey photometry of red giant branch stars to determine a
distance to the South-West Cloud of 793 +/- 45 kpc. The metallicity of the
cloud is found to be [Fe/H] = -1.3 +/- 0.1. This is consistent with the
coincident globular clusters PAndAS-7 and PAndAS-8, which have metallicities
determined using an independent technique of [Fe/H] = -1.35 +/- 0.15. We
measure a brightness for the Cloud of M_V = -12.1 mag; this is ~75 per cent of
the luminosity implied by the luminosity-metallicity relation. Under the
assumption that the South-West Cloud is the visible remnant of an accreted
dwarf satellite, this suggests that the progenitor object was amongst M31's
brightest dwarf galaxies prior to disruption.Comment: 13 pages, 9 figures, accepted for publication in MNRA
A Model for Integration and Interlinking of Idea Management Systems
This paper introduces the use of Semantic Web technologies for the Idea Management Systems as a gap closer between heterogeneous software and achieving interoperability. We present a model that proposes how and what kind of rich metadata annotations to apply in the domain of Idea Management Systems. In addition, as a part of our model, we present a Generic Idea and Innovation Management Ontology (GI2MO). The described model is backed by a set of use cases followed by evaluations that prove how Semantic Web can work as tool to create new opportunities and leverage the contemporary Idea Management legacy systems into the next level
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