525 research outputs found
Public Libraries and the Internet 2006
Examines the capability of public libraries to provide and sustain public access Internet services and resources that meet community needs, including serving as the first choice for content, resources, services, and technology infrastructure
Concept map assessment of classroom learning: Reliability, validity, and logistical practicality
Supergiant Shells and Molecular Cloud Formation in the LMC
We investigate the influence of large-scale stellar feedback on the formation
of molecular clouds in the Large Magellanic Cloud (LMC). Examining the
relationship between HI and 12CO(J=1-0) in supergiant shells (SGSs), we find
that the molecular fraction in the total volume occupied by SGSs is not
enhanced with respect to the rest of the LMC disk. However, the majority of
objects (~70% by mass) are more molecular than their local surroundings,
implying that the presence of a supergiant shell does on average have a
positive effect on the molecular gas fraction. Averaged over the full SGS
sample, our results suggest that ~12-25% of the molecular mass in supergiant
shell systems was formed as a direct result of the stellar feedback that
created the shells. This corresponds to ~4-11% of the total molecular mass of
the galaxy. These figures are an approximate lower limit to the total
contribution of stellar feedback to molecular cloud formation in the LMC, and
constitute one of the first quantitative measurements of feedback-triggered
molecular cloud formation in a galactic system.Comment: 14 pages, 6 figures. Accepted for publication in Ap
Libraries Connect Communities: Public Library Funding & Technology Access Study 2008-2009
Based on a survey of public libraries, examines trends in demand for, provision of, and quality of free computer and Internet services and in library budgets. Includes state data and suggestions for improving public access connectivity and infrastructure
HI Emission and Absorption in the Southern Galactic Plane Survey
We present preliminary results from the Southern Galactic Plane Survey (SGPS)
Test Region and Parkes data. As part of the pilot project for the Southern
Galactic Plane Survey, observations of a Test Region (325.5 deg < l < 333.5
deg; -0.5 deg < b < 3.5 deg) were completed in December 1998. Single dish
observations of the full survey region (253 deg < l < 358 deg; |b| <1 deg) with
the Parkes Radio Telescope were completed in March 2000. We present a sample of
SGPS HI data with particular attention to the smallest and largest scale
structures seen in absorption and emission, respectively. On the large scale,
we detect many prominent HI shells. On the small scale, we note extremely
compact, cold clouds seen in HI self-absorption. We explore how these two
classes of objects probe opposite ends of the HI spatial power spectrum.Comment: 9 pages, 3 embedded postscript & 4 jpeg figures. Presented at the
Astronomical Society of Australia, Hobart, Tasmania, July 4-7 2000. To appear
in PASA Vol. 18(1
Left ventricular outcomes following multivessel PCI vs. infarct artery-only PCI in patients with acute STEMI: the Glasgow PRAMI CMR sub-study
No abstract available
Molecular Clouds in Supershells: A Case Study of Three Objects in the Walls of GSH 287+04-17 and GSH 277+00+36
We present an in-depth case study of three molecular clouds associated with
the walls of the Galactic supershells GSH 287+04-17 and GSH 277+00+36. These
clouds have been identified in previous work as examples in which molecular gas
is either being formed or destroyed due to the influence of the shells.
12CO(J=1-0), 13CO(J=1-0) and C18O(J=1-0) mapping observations with the Mopra
telescope provide detailed information on the distribution and properties of
the molecular gas, enabling an improved discussion of its relationship to the
wider environment in which it resides. We find that massive star formation is
occurring in molecular gas likely formed in-situ in the shell wall, at a
Galactic altitude of ~200 pc. This second-generation star formation activity is
dominating its local environment; driving the expansion of a small HII region
which is blistering out of the atomic shell wall. We also find new
morphological evidence of disruption in two smaller entrained molecular clouds
thought to pre-date the shells. We suggest that at the present post-interaction
epoch, the lifetime of this surviving molecular material is no longer strongly
determined by the shells themselves.Comment: 26 pages, 10 figures, accepted for publication in the Astrophysical
Journa
Knowing what you know in brain segmentation using Bayesian deep neural networks
In this paper, we describe a Bayesian deep neural network (DNN) for
predicting FreeSurfer segmentations of structural MRI volumes, in minutes
rather than hours. The network was trained and evaluated on a large dataset (n
= 11,480), obtained by combining data from more than a hundred different sites,
and also evaluated on another completely held-out dataset (n = 418). The
network was trained using a novel spike-and-slab dropout-based variational
inference approach. We show that, on these datasets, the proposed Bayesian DNN
outperforms previously proposed methods, in terms of the similarity between the
segmentation predictions and the FreeSurfer labels, and the usefulness of the
estimate uncertainty of these predictions. In particular, we demonstrated that
the prediction uncertainty of this network at each voxel is a good indicator of
whether the network has made an error and that the uncertainty across the whole
brain can predict the manual quality control ratings of a scan. The proposed
Bayesian DNN method should be applicable to any new network architecture for
addressing the segmentation problem.Comment: Submitted to Frontiers in Neuroinformatic
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