Publications

The paragenesis, textures, and chemical compositions of magnetite in two mafic to intermediate intrusions and four IOA deposits in SE Missouri were studied to discriminate between igneous and hydrothermal sources. In this study, we found that replacement magnetite with mineral inclusion-rich cores yields erroneously high Ti, Al, Si, Mg, and Mn contents as determined by EMP and LA-ICP-MS...

This paper provides a brief summary of the history, development and variety of applications of electron microscopy techniques to analyze coals, organic-rich shales, and carbonaceous materials. General construction and principles of operation of transmitted (TEM) and scanning electron microscope (SEM) are outlined, along with guidance on specimen preparation, and a brief overview of...

California provides wintering habitat for most greater white-fronted geese (Anser albifrons [GWFG]) in the Pacific Flyway and this population has rapidly increased since the 1980s. Increased harvest of GWFG wintering in California may prevent agricultural depredation while providing increased hunting opportunities. However, changes in harvest levels are unlikely to be uniform across the...

Extensional deformation in the lower to middle continental crust is increasingly recognized and shown to have significant impact on crustal architecture, magma emplacement, fluid flow, and ore deposits. Application of the concept of extensional strain to ancient orogenic systems, like the Grenville province of eastern North America, has helped decipher the structural evolution of these...

The Laboratory for Infectious Disease and the Environment (LIDE) studies the occurrence, fate and transport, and health effects of human and agricultural zoonotic pathogens in the environment. The LIDE is an interagency collaborative effort between the U.S. Geological Survey and the U.S. Department of Agriculture-Agricultural Research Service that conducts research to inform decision...

Regulations for public water systems (PWS) in the U.S. consider Cryptosporidium a microbial contaminant of surface water supplies. Ground- water is assumed free of Cryptosporidium unless surface water is entering supply wells. We determined the incidence of Cryptosporidium in PWS wells varying in surface water influence. Community and noncommunity PWS wells (n = 145) were sampled (n = 964...

Isotopic ratios have long been used to learn about physical processes acting over a wide range of geological environments, and in constraining the origin and/or evolution of planetary bodies. We report the spectroscopic detection of deuterium in Saturn's rings and satellites, and use these measurements to determine the (D/H) ratios in their near-surface regions. Saturn's moons, Phoebe...

Water and sediment extracts samples were analyzed for extractable hydrocarbons by gas chromatography/mass spectrometry (GC/MS) using an Agilent (Agilent Technologies, Palo Alto, CA, USA) 7890 series GC and 5975 electron ionization (EI) mass selective detector (MSD) operated in scan mode. Agilent ChemStation software was used for data acquisition and analysis (version E.02.00.493 on GC/MS...

Remote sensing has been hailed as a promising technology to provide spatially explicit information on tree species distribution. Such information is of high value for ecologists and forest managers, particularly in tropical environments in which it is acquired by costly field inventories performed at the plot level (∼1 ha). Over the last decade, hyperspectral sensors, usually on board...

Most of Hawaii's endemic avifauna are species of conservation concern. Some of Hawaii's endangered waterbirds, however, have increased in number as a result of intensive management of wetlands. To inform these conservation efforts, we examined interisland genetic structure and gene flow within 2 Hawaiian endemic waterbirds, the Hawaiian Coot (Fulica alai) and the Hawaiian subspecies of...

Natural history collections spanning multiple decades provide fundamental historical baselines to measure and understand changing biodiversity. New technologies such as next generation DNA sequencing (NGS) have considerably increased the potential of museum specimens to address significant questions regarding the impact of environmental changes on host and parasite/pathogen dynamics. We...

Fecal contamination by human and animal pathogens, including viruses, bacteria, and protozoa, is a potential human health hazard, especially with regards to drinking water. Pathogen occurrence in groundwater varies considerably in space and time, which can be difficult to characterize as sampling typically requires hundreds of liters of water to be passed through a filter. Here we...