53 research outputs found
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Trauma in War, Trauma in Life: The Pose of the Heroic Battlefield Correspondent
Discusses the effects of war trauma, particularly posttraumatic stress disorder (PTSD), on the writing and attitudes of notable journalist-literary figures such as Hemingway, Stephen Crane, and Rudyard Kipling. Underwood explores the reasons why some writers, including Hemingway, embrace high-risk engagement with war reporting while others avoid it. Delving into the heroic code of courageous journalistic conduct as understood by Hemingway and other writers dealing with psychological stress, Underwood argues that Hemingway is torn between the heroic code and his PTSD/sentimentalism, the latter expressed in The Sun Also Rises and A Farewell to Arms. Points out that Hemingway’s solipsistic World War II reporting contains none of the “honest and authentic journalistic prose that his novels had made famous.” In contrast, Underwood briefly describes the “selfless and detached” war reporting of Martha Gellhorn
Trauma, News, and Narrative: The Study of Violence and Loss in Journalism and Fiction
Connects Hemingway’s dysfunctional family history, excessive risk-taking, and traumatic experiences to his journalistic and literary achievements
A preliminary analysis of the InfiniPath and XD1 network interfaces
Two recently delivered systems have begun a new trend in cluster interconnects. Both the InfiniPath network from PathScale, Inc., and the RapidArray fabric in the XD1 system from Cray, Inc., leverage commodity network fabrics while customizing the network interface in an attempt to add value specifically for the high performance computing (HPC) cluster market. Both network interfaces are compatible with standard InfiniBand (IB) switches, but neither use the traditional programming interfaces to support MPI. Another fundamental difference between these networks and other modern network adapters is that much of the processing needed for the network protocol stack is performed on the host processor(s) rather than by the network interface itself. This approach stands in stark contrast to the current direction of most high-performance networking activities, which is to offload as much protocol processing as possible to the network interface. In this paper, we provide an initial performance comparison of the two partially custom networks (PathScale’s InfiniPath and Cray’s XD1) with a more commodity network (standard IB) and a more custom network (Quadrics Elan4). Our evaluation includes several micro-benchmark results as well as some initial application performance data. 1
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