Is a local bar a good place to find a companion? The near infrared morphology of Maffei 2

Maffei 2 is one of the closest large spiral galaxies lying just beyond the Local Group. It would probably be one of the most heavily studied galaxies in the sky were it not for the approximately 5 magnitudes of visual extinction resulting from its position behind the Galactic plane. It is the site of a burst of nuclear star formation indicated by strong infrared and radii continuum emission. Interferometric maps of CO-12 and CO-13 emission indicate that star formation is associated with a barlike structure consisting of arms of molecular gas that extend from within approximately 50 pc of the dynamical center out to a radius of at least 500 pc. HI maps have shown the galaxy to have an angular extent of approximately 15 feet and a neutral gas mass typical of a large spiral galaxy

Geometry and Destiny

The recognition that the cosmological constant may be non-zero forces us to re-evaluate standard notions about the connection between geometry and the fate of our Universe. An open Universe can recollapse, and a closed Universe can expand forever. As a corollary, we point out that there is no set of cosmological observations we can perform that will unambiguously allow us to determine what the ultimate destiny of the Universe will be.Comment: 7 pages, Gravity Research Foundation Essa

A synthesis of aquatic science for management of Lakes Mead and Mohave: U.S. Geological Survey Circular 1381

Lake Mead provides many significant benefits that have made the modern development of the southwestern United States possible. The lake also provides important aquatic habitat for a wide variety of wildlife including endangered species, and a diversity of world-class water based recreational opportunities for more than 8 million visitors annually. It is one of the most extensively used and intensively monitored reservoirs in the United States. The largest reservoir by volume in the United States, it supplies critical storage of water supplies for more than 25 million people in three western states (California, Arizona, and Nevada). Storage within Lake Mead supplies drinking water and the hydropower to provide electricity for major cities including Las Vegas, Phoenix, Los Angeles, Tucson, and San Diego, and irrigation of greater than 2.5 million acres of croplands. Due to the importance of Lake Mead, multiple agencies are actively involved in its monitoring and research. These agencies have a long history of collaboration in the assessment of water quality, water-dependent resources, and ecosystem health. In 2004, the National Park Service obtained funds from the Southern Nevada Public Lands Management Act to enhance this partnership and expand monitoring and research efforts to increase the overall understanding of Lake Mead and Lake Mohave. Participating agencies included the National Park Service, Southern Nevada Water Authority, U.S. Geological Survey, Nevada Department of Wildlife, Bureau of Reclamation, U.S. Fish and Wildlife Service, University of Nevada, Las Vegas, and University of Nevada, Reno. Results of these important efforts have been presented in Lake Mead Science Symposia conducted in 2009 and 2012. The relationships forged by the collaboration led to the development in 2012 of the Lake Mead Ecosystem Monitoring (LaMEM) Work Group, which has formalized the partnership and documented an interagency purpose and mission statement with common objectives for protection of Lake Mead and Lake Mohave water quality and water-dependent resources. This Circular has been developed to summarize the state of the knowledge related to the interests and objectives of the LaMEM Work Group, to inform management and the public of current lake conditions, and identify future needs for monitoring and research. It is hoped that this report will provide a framework for continued long-term investigations and analysis of the environmental health of Lakes Mead and Mohave

Salinity History of Coastal Marshes Reconstructed from Diatom Remains

Sediment cores were collected from three Louisiana coastal marsh ponds, dated with radioisotopes, and analyzed for diatom remains to determine if long-term salinity changes were evident in the sediment record. A diatom-based salinity index formulated from a statistical comparison of available salinity data and changing diatom assemblages demonstrated that diatom remains appear to preserve salinity signals in coastal brackish and salt marsh environments. The salinity index was applied to sediment cores spanning the late 1600s to the 1990s and provided a more complete record of salinity than field data, which were temporally and spatially incomplete. The salinity reconstructions indicated that salinity has increased at two sites and decreased at a third since the early 1900s. The salinity changes are less than 1‰ per decade in all cases, and may be due to natural variability as depicted by the wide range of salinities observed between the late 1600s and 1900. Salinity regimes may be very localized (\u3c2 km from a hydrologic source), indicating single-site studies may not be applicable to regional inferences. This study demonstrates that diatoms can be used to reconstruct past salinity in coastal marsh environments and can provide a useful tool with which to study the changing hydrology of river-influenced ecosystems

Riodinid butterfly fauna (Lepidoptera) of the Cosñipata Region, Peru: Annotated checklist, community structure, and contrast with Lycaenidae

A team of experienced lepidopterists sampled the butterfly fauna of Peru’s Cosñipata Region from 400 to 4,000 m elevation for more than a decade (7,440 field person-hours) and supplemented this sam­ple with data from museum specimens and the scientific literature. An annotated checklist of Cosñipata Riodinidae (Lepidoptera: Papilionoidea) documents 398 species, which represents 29% of the world Rio­dinidae fauna. For each, it lists sample abundance, adult behavior, elevation, and temporal distribution. In the fieldwork sample, 75 species (20.9%) were sampled once and 39 (9.8%) were not encountered (collected or imaged by others). A riodinid species of median abundance was sampled an average of once every 826 field person-hours. Sampled sex ratios were 81.2% male, but were not statistically higher in species in which male perching behavior was observed. We document examples of conspicuous geographic variation in the time of male perching behavior. Species richness is greatest at low elevation and at the transition between the dry and wet seasons. There is little evidence that the community is composed of species restricted to narrow elevational bands or restricted in the adult stage to a single season. Compared with Lycaenidae, Riodinidae are significantly more restricted to lowland habitats and were sampled 2.5 times as frequently with a mean number of individuals per species more than twice as great as that of Lycaenidae

Photoelectrochemical Hydrogen Evolution Using Si Microwire Arrays

Arrays of B-doped p-Si microwires, diffusion-doped with P to form a radial n+ emitter and subsequently coated with a 1.5-nm-thick discontinuous film of evaporated Pt, were used as photocathodes for H_2 evolution from water. These electrodes yielded thermodynamically based energy-conversion efficiencies >5% under 1 sun solar simulation, despite absorbing less than 50% of the above-band-gap incident photons. Analogous p-Si wire-array electrodes yielded efficiencies <0.2%, largely limited by the low photovoltage generated at the p-Si/H_2O junction