LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

This work was supported by The Department of the Interior Alaska Climate Adaptation Science Center, which is managed by the USGS National Climate Adaptation Science Center.

53 pages : color illustrations, color maps ; 28 cmThis report is designed as a living document to inform the community, decision makers, and academics and to serve as a learning and teaching tool. The nine key messages summarized on pages 6 and 7 are intended for use as a quick reference. Unique for this type of report, these key messages highlight actions by Juneau's civil society, including local nonprofit organizations.We thank the City and Borough of Juneau (CBJ) for its support in bringing this vital information on climate change to the Juneau community and to others. Thanks especially to all the co-authors and other contributors. The inclusion of such a diverse array of material, including local knowledge, was made possible by the many elders, scientists, and local experts who contributed their time and expertise. The report is online at acrc.alaska.edu/ juneau-climate-report. It is an honor to be the lead editor and project manager for this critical effort. We have a chance to save our world from the most extreme effects of climate change. Let us take it. Gunalchéesh, sincerely, James E. Powell (Jim), PhD, Alaska Coastal Rainforest Center, UASWelcome / Thomas F. Thornton -- Juneau's climate report: History and background / Bruce Botelho -- Using this report -- Acknowledgements / James E. Powell -- A regional Indigenous perspective on adaptation: The Central Council of Tlingit & Haida Indian Tribes of Alaska's Climate Change Adaptation Plan / Raymond Paddock -- Nine key messages -- What we're experiencing: Atmospheric, marine, terrestrial, and ecological effects. Climate. Setting and seasons / Tom Ainsworth -- More precipitation / Rick Thoman -- Higher temperatures / Rich Thoman -- Less snowfall / Eran Hood -- Ocean. Surface uplift and sea level rise / Eran Hood -- Extensive effects of a warming ocean / Heidi Pearson -- Increasing ocean acidification / Robert Foy -- Land. More landslides / Sonia Nagorski & Aaron Jacobs -- Mendenhall Glacier continues to retreat / Jason Amundson -- Tongass Forest impacts and carbon / Dave D'Amore -- Animals. Terrestrial vertebrates in A¿¿ak'w & T'aak¿łu Aani¿¿ / Richard Carstensen -- Three animals as indicators of change / Richard Carstensen -- Insects / Bob Armstrong -- What we're doing: Community response. Upgrading ifrastructure and mitigation / Katie Koester -- Upgrading utilities and other energy consumers / Alec Mesdag -- Growing demand for hydropower / Duff Mitchell -- Leading a shift in transportation / Duff Mitchell -- Maintaining mental health through community and recreation / Linda Kruger & Kevin Maier -- Food security / Darren Snyder & Jim Powell -- Large cruise ship air emissions / Jim Powell -- Tourists' views on climate change mitigation / Jim Powell -- Lowering greenhouse gas emissions / Jim Powell & Peggy Wilcox -- Residents taking action / Andy Romanoff & Jim Powell -- Summary and Recommendations -- References -- Graphics and data sources -- Appendix: Juneau nonprofit climate change organization

State of Nearshore Processes Research: II

Report Based on the Nearshore Research Workshop, St. Petersburg, Florida, September 14-16, 1998, Technical Report NPS-OC-00-001Understanding nearshore processes is increasingly important because the majority of the world’s coastlines are eroding. The increased threat of global warming and the resulting rise in sea level may accelerate erosion problems. Beaches are a primary recreational area, are essential to commerce, and are important to nation defense, especially since the end of the cold war. Increasing our knowledge of nearshore process is crucial both economically and militarily.Sponsored by the: National Science Foundation, National Oceanic & Atmospheric Administration, Office of Naval Research, U.S. Army Corps of Engineers, and U.S. Geological Surve

Primary school students' statistical thinking: a comparison of two australian states

A framework for teaching and assessing statistical thinking comprising four constructs and four levels for each construct, has been developed and the framework validated using data from 20 US students in Years 1 - 5. The same validation· procedures· were implemented in two different cohorts, totalling 40 subjects, of Australian students in Years 1 - 5. Lower levels of coherence were found. This paper reports the Australian data, seeks to address reasons for the differences and compares the levels of performance between the Australian and US students

A Shaftless Magnetically Levitated Multifunctional Spacecraft Flywheel Storage System

Presently many types of spacecraft use a Spacecraft Attitude Control System (ACS) with momentum wheels for steering and electrochemical batteries to provide electrical power for the eclipse period of the spacecraft orbit. Future spacecraft will use Flywheels for combined use in ACS and Energy Storage. This can be done by using multiple wheels and varying the differential speed for ACS and varying the average speed for energy storage and recovery. Technology in these areas has improved since the 1990s so it is now feasible for flywheel systems to emerge from the laboratory for spacecraft use. This paper describes a new flywheel system that can be used for both ACS and energy storage. Some of the possible advantages of a flywheel system are: lower total mass and volume, higher efficiency, less thermal impact, improved satellite integration schedule and complexity, simplified satellite orbital operations, longer life with lower risk, less pointing jitter, and greater capability for high-rate slews. In short, they have the potential to enable new types of missions and provide lower cost. Two basic types of flywheel configurations are the Flywheel Energy Storage System (FESS) and the Integrated Power and Attitude Control System (IPACS)