2,735 research outputs found
The State of the Great Central Valley -- The Environment
Part of a series that provides various quality of life indicators for California's Central Valley. Includes data on air quality, water, and land use. Highlights successful efforts that combine goals of economic growth and environmental stewardship
Suppression of Supergravity Anomalies in Conformal Sequestering
We show that the anomaly-mediated supersymmetry breaking via the Kahler and
sigma-model anomalies is suppressed by conformal dynamics in the supersymmetry
breaking sector.Comment: 8 page
Text Segmentation Using Exponential Models
This paper introduces a new statistical approach to partitioning text
automatically into coherent segments. Our approach enlists both short-range and
long-range language models to help it sniff out likely sites of topic changes
in text. To aid its search, the system consults a set of simple lexical hints
it has learned to associate with the presence of boundaries through inspection
of a large corpus of annotated data. We also propose a new probabilistically
motivated error metric for use by the natural language processing and
information retrieval communities, intended to supersede precision and recall
for appraising segmentation algorithms. Qualitative assessment of our algorithm
as well as evaluation using this new metric demonstrate the effectiveness of
our approach in two very different domains, Wall Street Journal articles and
the TDT Corpus, a collection of newswire articles and broadcast news
transcripts.Comment: 12 pages, LaTeX source and postscript figures for EMNLP-2 pape
Computational fluid dynamics for propulsion technology: Geometric grid visualization in CFD-based propulsion technology research
The coordination is examined of necessary resources, facilities, and special personnel to provide technical integration activities in the area of computational fluid dynamics applied to propulsion technology. Involved is the coordination of CFD activities between government, industry, and universities. Current geometry modeling, grid generation, and graphical methods are established to use in the analysis of CFD design methodologies
Filamentary Star Formation: Observing the Evolution toward Flattened Envelopes
Filamentary structures are ubiquitous from large-scale molecular clouds (few
parsecs) to small-scale circumstellar envelopes around Class 0 sources (~1000
AU to ~0.1 pc). In particular, recent observations with the Herschel Space
Observatory emphasize the importance of large-scale filaments (few parsecs) and
star formation. The small-scale flattened envelopes around Class 0 sources are
reminiscent of the large-scale filaments. We propose an observationally derived
scenario for filamentary star formation that describes the evolution of
filaments as part of the process for formation of cores and circumstellar
envelopes. If such a scenario is correct, small-scale filamentary structures
(0.1 pc in length) with higher densities embedded in starless cores should
exist, although to date almost all the interferometers have failed to observe
such structures. We perform synthetic observations of filaments at the
prestellar stage by modeling the known Class 0 flattened envelope in L1157
using both the Combined Array for Research in Millimeter-wave Astronomy (CARMA)
and the Atacama Large Millimeter/Submillimeter Array (ALMA). We show that with
reasonable estimates for the column density through the flattened envelope, the
CARMA D-array at 3mm wavelengths is not able to detect such filamentary
structure, so previous studies would not have detected them. However, the
substructures may be detected with CARMA D+E array at 3 mm and CARMA E array at
1 mm as a result of more appropriate resolution and sensitivity. ALMA is also
capable of detecting the substructures and showing the structures in detail
compared to the CARMA results with its unprecedented sensitivity. Such
detection will confirm the new proposed paradigm of non-spherical star
formation.Comment: 9 pages, 10 figures. Accepted by Ap
Kompaneets Model Fitting of the Orion-Eridanus Superbubble
Winds and supernovae from OB associations create large cavities in the
interstellar medium referred to as superbubbles. The Orion molecular clouds are
the nearest high mass star-forming region and have created a highly elongated,
20 degree x 45 degree, superbubble. We fit Kompaneets models to the
Orion-Eridanus superbubble and find that a model where the Eridanus side of the
superbubble is oriented away from the Sun provides a marginal fit. Because this
model requires an unusually small scaleheight of 40 pc and has the superbubble
inclined 35 degrees from the normal to the Galactic plane, we propose that this
model should be treated as a general framework for modelling the Orion-Eridanus
superbubble, with a secondary physical mechanism not included in the Kompaneets
model required to fully account for the orientation and elongation of the
superbubble.Comment: 15 pages, 5 figures, 2 tables, accepted by MNRAS, minor grammatical
change
Online mentoring and peer support: Using learning technologies to facilitate entry into a community of practice
A vital aspect of any professional education is the opportunity for students to engage in meaningful practical experiences. In pre‐service teacher education in Australia, this vital teaching practice component has undergone challenges in recent years due to increasing student numbers (linked to the increasing demand for new teachers) and limited resources in university and school sectors. As such, initiatives to enhance the practical component of this professional degree have been sought. This paper details the methodology and outcomes associated with a pilot project that utilized asynchronous Web‐based communication tools to facilitate mentoring and peer support through the teaching practice experience. Analysis of the online discussions and interviews with participants provides an indication of the nature of the interactions and the perceived value of the intervention, and informs the potential for larger‐scale implementation
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