32 research outputs found

    The Science Performance of JWST as Characterized in Commissioning

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    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

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    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 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m 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

    Staying warm is not always the norm: Behavioural differences in thermoregulation of two snake species

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    Thermal biology research compares field with laboratory data to elucidate the evolution of temperature-sensitive traits in ectotherms. The hidden challenge of many of these studies is discerning whether animals actively thermoregulate, since motivation is not typically assessed. By studying behaviours involved in thermoregulation, we can better understand the mechanisms behind body temperature control. Using an integrative approach, we assess thermoregulatory and thermotactic behaviours of two sympatric snake species with contrasting life histories, the generalist Thamnophis sirtalis sirtalis (Linnaeus, 1758) and the semi-fossorial Storeria occipitomaculata occipitomaculata (Storer, 1839). We expected that thermoregulatory behaviours would be optimised based on life history, in that T. s. sirtalis would show higher evidence for thermally-oriented behaviours than S. o. occipitomaculata due to its active nature. Thamnophis s. sirtalis actively thermoregulated, had higher thermal preferences (29.4 2.5 vs. 25.3 3.6C), and was more active than S. o. occipitomaculata, which showed relatively low evidence for thermotaxis. Our results build on the notion that evaluating movement patterns and rostral orientation towards a heat-source can help ascertain whether animals make thermally-motivated choices. Our data give insight into the thermoregulatory strategies used by snakes with different life histories, and maximise the information provided by behavioural thermoregulation experiments.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

    Syntactic and Semantic Type and Selection. SPARKLE Deliverable 5.2

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    This document describes research on techniques for semantic annotation of subcategorization frames involving semantic classification of heads of phrases. In keeping with the Sparkle policy of exploring alternative approaches, the methods vary widely in statistical models using (i) the minimum description principle, (ii) analogy-based semantic similary, (iii) EM-based clustering, and (iv) Markov models induced by semantic class hierarchie
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