20 research outputs found
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 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
point-source depth in a single visit in will be (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 with
, and will be imaged multiple times in six bands, ,
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 region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . 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
Building International Business Theory: A Grounded Theory Approach
The field of international business (IB) is in need of more theory development (Morck & Yeung, 2007). As such, the main focus of our manuscript was to provide guidance on how to build IB specific theory using grounded theory (GT). Moreover, we contribute to future theory development by identifying areas within IB where GT can be applied and the type of research issues that can be addressed using this methodology. Finally, we make a noteworthy contribution by discussing some of GTâs caveats and limitations, particularly those relevant to IB. This effort is intended to spur further interest in the development of IB theory
Rusty Blackbird Habitat Selection and Survivorship during Nesting and Post-Fledging
Rusty blackbird (Euphagus carolinus) populations have declined dramatically since the 1970s and the cause of decline is still unclear. As is the case for many passerines, most research on rusty blackbirds occurs during the nesting period. Nest success is relatively high in most of the rusty blackbird’s range, but survival during the post-fledging period, when fledgling songbirds are particularly vulnerable, has not been studied. We assessed fledgling and adult survivorship and nest success in northern New Hampshire from May to August in 2010 to 2012. We also assessed fledgling and adult post-fledging habitat selection and nest-site selection. The likelihood of rusty blackbirds nesting in a given area increased with an increasing proportion of softwood/mixed-wood sapling stands and decreasing distances to first to sixth order streams. Wetlands were not selected for nest sites, but both adults and fledglings selected wetlands for post-fledging habitat. Fledglings and adults selected similar habitat post-fledging, but fledglings were much more likely to be found in habitat with an increasing proportion of softwood/mixed-wood sapling stands and were more likely to be closer to streams than adults. No habitat variables selected during nesting or post-fledging influenced daily survival rates, which were relatively low for adults over the 60-day study periods (males 0.996, females 0.998). Fledgling survival rates (0.89) were much higher than reported for species of similar size
Migratory connectivity and annual cycle phenology of Rusty Blackbirds (Euphagus carolinus) revealed through archival GPS tags
Understanding spatial and temporal movement patterns of migratory birds throughout the annual cycle can help identify potential population threats. The behavior and habitat use of birds during migration and stopover periods is particularly understudied in many species. In this study, we used high spatial resolution archival GPS tags to track Rusty Blackbirds (Euphagus carolinus) from one eastern (New Hampshire) and two western (Alaska and Alberta) breeding populations across the annual cycle. We sought to determine: 1) migratory connectivity of the three distinct populations; 2) migratory phenology, behavior, and time spent during each phase of the annual cycle; and 3) habitat use of individuals throughout the nonbreeding period. We retrieved 7 tags from 30 tagged individuals following 1-year deployments. We found that four Alberta individuals overwintered in the Mississippi Alluvial Valley, two Alaska individuals overwintered in either the Great Plains or the Mississippi Alluvial Valley, and the single New Hampshire individual overwintered on the Southeastern Coastal Plain. Length of annual cycle stages varied among individuals, with the combined migratory periods occupying between 12% and 48% of the annual cycle. Stopover behavior was also widely variable, as minimum convex polygons of stopovers ranged from < 1 hectare to 505 kmÂČ and stopover durations ranged from 1 to 35 days (n = 40 stopovers). Birds predominantly used woody wetlands and emergent marsh during the nonbreeding period, but habitat use differed between roosting and foraging. Marshes were used more for nocturnal roosting, whereas woody wetlands were used for diurnal foraging. Our results can help efforts to conserve this declining species by targeting regions and habitats at specific times of year for management during the nonbreeding period. In particular, the large amount of time spent during migration periods suggests conservation efforts in stopover regions are just as important as those on the wintering grounds