THE HIGH CADENCE TRANSIENT SURVEY (HITS). I. SURVEY DESIGN AND SUPERNOVA SHOCK BREAKOUT CONSTRAINTS

Indexación: Web of Science; Scopus.We present the first results of the High Cadence Transient Survey (HiTS), a survey for which the objective is to detect and follow-up optical transients with characteristic timescales from hours to days, especially the earliest hours of supernova (SN) explosions. HiTS uses the Dark Energy Camera and a custom pipeline for image subtraction, candidate filtering and candidate visualization, which runs in real-time to be able to react rapidly to the new transients. We discuss the survey design, the technical challenges associated with the real-time analysis of these large volumes of data and our first results. In our 2013, 2014, and 2015 campaigns, we detected more than 120 young SN candidates, but we did not find a clear signature from the short-lived SN shock breakouts (SBOs) originating after the core collapse of red supergiant stars, which was the initial science aim of this survey. Using the empirical distribution of limiting magnitudes from our observational campaigns, we measured the expected recovery fraction of randomly injected SN light curves, which included SBO optical peaks produced with models from Tominaga et al. (2011) and Nakar & Sari (2010). From this analysis, we cannot rule out the models from Tominaga et al. (2011) under any reasonable distributions of progenitor masses, but we can marginally rule out the brighter and longer-lived SBO models from Nakar & Sari (2010) under our best-guess distribution of progenitor masses. Finally, we highlight the implications of this work for future massive data sets produced by astronomical observatories, such as LSST.http://iopscience.iop.org/article/10.3847/0004-637X/832/2/155/meta;jsessionid=76BDFFFE378003616F6DBA56A9225673.c4.iopscience.cld.iop.or

Monitoring the Effects of Ground-water Withdrawals from the N Aquifer in the Black Mesa Area, Northeastern Arizona

In 1968, Peabody Coal Company began strip-mining operations on land leased from the Navajo and Hopi Tribes on Black Mesa (fig. 1). Of the 11 to 13 million tons of coal that are extracted each year, an average of about 5 million tons are transported as slurry by a 273-mile-long pipeline from the coal-lease area west to the Mohave Generating Station near Laughlin, Nevada. Transporting the coal in slurry form consumes, on average, about 3,800 acre-ft of water annually. The slurry water is provided through a network of 8 wells that tap the confined parts of the D and N aquifers underlying Black Mesa. Most of the slurry water is pumped from the confined part of the N aquifer which also is the primary source of water for municipal users within the 5,400-square-mile Black Mesa area. The Navajo Nation and Hopi Tribe became concerned about the long term effects of industrial withdrawals from the N aquifer on the availability and quality of water supplies for domestic and municipal purposes. These concerns led to an ongoing investigation of the water resources of the Black Mesa area begun in 1971 by the U.S. Geological Survey (USGS) in cooperation with the Arizona Department of Water Resources (ADWR) and the Bureau of Indian Affairs (BIA)

Occurrence and quality of surface water and ground water within the Yavapai-Prescott Indian Reservation, central Arizona, 1994-98 /

Includes bibliographical references (p. 36-38).Mode of access: Internet

Comparison of Preconstruction and 2003 Bathymetric and Topographic Surveys of Lake McConaughy, Nebraska

The U.S. Geological Survey, in cooperation with The Central Nebraska Public Power and Irrigation District, conducted a study that used bathymetric and topographic surveying in conjunction with Geographical Information Systems techniques to determine the 2003 physical shape, current storage capacity, and the changes in storage capacity of Lake McConaughy that have occurred over the past 62 years. By combining the bathymetric and topographic survey data, the current surface area of Lake McConaughy was determined to be 30,413.0 acres, with a volume of 1,756,300 acre-feet at the lake conservation-pool elevation of 3,266.4 feet above North American Vertical Datum of 1988 (3,265.0 feet above Central datum). To determine the changes in storage of Lake McConaughy, the 2003 survey Digital Elevation Model (DEM) was compared to a preconstruction DEM compiled from historical contour maps. This comparison showed an increase in elevation at the dam site due to the installation of Kingsley Dam. Immediately to the west of the Kingsley Dam is an area of decline where a borrow pit for Kingsley Dam was excavated. The comparison of the preconstruction survey to the 2003 survey also was used to estimate the gross storage capacity reduction that occurred between 1941 and 2002. The results of this comparison indicate a gross storage capacity reduction of approximately 42,372 acre-feet, at the lake conservation-pool elevation of 3,266.4 feet in NAVD 88 (3,265.0 feet in Central datum). By comparing preconstruction and 2003 survey data and subtracting the Kingsley Dam and borrow pit, the total estimated net volume of sediment deposited over the past 62 years is 53,347,124 cubic yards, at an annual average rate of 860,437 cubic yards per year. The approximate decrease in the net storage capacity occurring over the past 62 years is 33,066 acre-feet, at an annual average decrease of approximately 533 acre-feet per year, which has resulted in a 1.8 percent decrease in storage capacity of Lake McConaughy. The lake has accumulated most of the sediment in the original river channel and in the west end of the delta area on the upstream end of the lake

Results of ground-water, surface-water, and water-quality monitoring, Black Mesa area, northeastern Arizona, 1990-91 /

"May 1992."Shipping list no.: 92-0465-P.Includes bibliographical references (p. 30-32).Mode of access: Internet

Results of ground-water, surface-water, and water-quality monitoring, Black Mesa area, northeastern Arizona, 1992-93 /

Shipping list no.: 96-0008-P.Includes bibliographical references (p. 36-37).Mode of access: Internet

Results of ground-water, surface-water, and water-quality monitoring, Black Mesa area, northeastern Arizona, 1991-92 /

"July 1993."Shipping list no.: 93-0525-P.Includes bibliographical references (p. 22-23).Mode of access: Internet

Results of ground-water, surface-water, and water-chemistry monitoring, Black Mesa area, northeastern Arizona, 1994 /

Shipping list no.: 96-0144-P.Includes bibliographical references (p. 23-25).Mode of access: Internet

A moral panic over cats

Some conservationists believe that free-ranging cats pose an enormous risk to biodiversity and public health and therefore should be eliminated from the landscape by any means necessary. They further claim that those who question the science or ethics behind their arguments are science deniers (merchants of doubt) seeking to mislead the public. As much as we share a commitment to conservation of biodiversity and wild nature, we believe these ideas are wrong and fuel an unwarranted moral panic over cats. Those who question the ecological or epidemiological status of cats are not science deniers, and it is a false analogy to compare them with corporate and right-wing special interests that perpetrate disinformation campaigns over issues, such as smoking and climate change. There are good conservation and public-health reasons and evidence to be skeptical that free-ranging cats constitute a disaster for biodiversity and human health in all circumstances. Further, there are significant and largely unaddressed ethical and policy issues (e.g., the ethics and efficacy of lethal management) relative to how people ought to value and coexist with cats and native wildlife. Society is better served by a collaborative approach to produce better scientific and ethical knowledge about free-ranging cats