Western Massasauga (Sistrurus tergeminus): Species Conservation Assessment

The primary goal in development of at-risk species conservation assessments is to compile biological and ecological information that may assist conservation practitioners in making decisions regarding the conservation of species of interest. The Nebraska Natural Legacy Project recognizes the Western Massasauga (Sistrurus tergeminus) as a Tier I at-risk species. Provided are some general management recommendations regarding Western Massasaugas. Conservation practitioners will need to use professional judgment to make specific management decisions based on objectives, location, and a multitude of variables. This resource was designed to share available knowledge of this at-risk species that will aid in the decision-making process or in identifying research needs to benefit the species. Species conservation assessments will need to be updated as relevant scientific information becomes available and/or conditions change. Though the Nebraska Natural Legacy Project focuses efforts in the state’s Biologically Unique Landscapes, it is recommended that whenever possible, practitioners make considerations for a species throughout its range in order to increase the outcome of successful conservation efforts. And in the case of conservation for massasaugas, it is particularly necessary to take into account the seasonal needs of the species and conserve both wintering and summer foraging habitat. Criteria for selection as Tier I State listed, G3T3 Trends since 2005 in NE Stable Range in NE Very southeast portion of state Habitat Wet mesic tallgrass prairie, wet meadow/marsh/wet prairie, lower-middle tallgrass prairie, cordgrass wet prairie, crayfish burrows Threats Loss/degradation of tallgrass prairie habitat, woody invasion, tilling for agriculture, prescribed fires, haying, vehicle mortality, persecution by humans Climate Change Vulnerability Index: Highly Vulnerable (NatureServe 2013) Research/Inventory Determine size/extent of Colfax County population; conduct surveys to assess distribution and abundance; conduct population monitoring and population viability assessment Landscapes Lower Platte River, Sandstone Prairies, Southeast Prairie

Description and outcomes of a simple surgical technique to treat thrombosed autogenous accesses

ObjectiveOwing to the difficulty of removing acute and chronic thrombus from autogenous accesses (AA) by standard surgical and endovascular techniques, many surgeons consider efforts to salvage a thrombosed AA as being futile. We describe a simple technique to extract acute and chronic thrombus from a failed AA. This technique involves making an incision adjacent to the anastomosis, directly extracting the arterial plug, and manually milking thrombus from the access. This report details the outcomes of a series of thrombosed AAs treated by surgical thrombectomy/intervention using this technique for manual clot extraction.MethodsA total of 146 surgical thrombectomies/interventions were performed in 102 patients to salvage a thrombosed AA. Mean follow-up was 15.6 months. Office, hospital, and dialysis unit records were reviewed to identify patient demographics, define procedure type, and determine functional patency rates. Kaplan-Meier survival analysis was used to estimate primary and secondary functional patency rates.ResultsComplete extraction of thrombus from the AA was achieved in 140 of 146 cases (95%). The studied procedure itself was technically successful in 127 cases (87%). Reasons for failure were the inability to completely extract thrombus from the AA in six, failed angioplasty due to long segment vein stenosis or sclerosis in seven or vein rupture in two, and central vein occlusion in one. Three failures occurred for unknown causes ≤3 days of successful thrombectomy. No single factor analyzed (age, sex, race, diabetes status, access type or location) was associated with technical failure. The estimated primary and secondary functional patency rates were 27% ± 5% and 61% ± 6% at 12 months.ConclusionsThe manual clot extraction technique described in this report effectively removed acute and chronic thrombus from failed AAs. Its use, combined with an intervention to treat the underlying cause for AA failure, significantly extended access durability

Corrosion of Civil War Era Sub Marine Explorer—Part 1

The Sub Marine Explorer is one of five submersibles (submarines) constructed prior to 1870 that have survived either in museums or as in situ archaeological sites around the world. Since 1869, the wreck of Explorer has emerged at low tide on the beach of Isla San Telmo, Archipiélago de las Perlas, Panama, located ~75 km southwest of Panama City in the Bay of Panama. In 2001, James Delgado visited the site. Locals described the wreck as a World War II-era Japanese midget submarine. Delgado consulted with Richard Wills, an expert on American Civil War submarines, and confirmed that the well-preserved wreck was the Sub Marine Explorer from the Civil War period

Corrosion of Civil War Era \u3ci\u3eSub Marine Explorer\u3c/i\u3e—Part 2

The Sub Marine Explorer was designed and built by Julius H. Kroehl, who was born in Prussia in 1820. After migrating to the United States in 1838 and becoming a citizen, he served in the Union Navy (United States Navy during the Civil War) as an underwater demolitions expert. He left the Navy in 1863 and began designing a “sub-marine” that would facilitate Union forces’ mine removal and obstruction clearance. At the end of the Civil War, he became an engineer for the Pacific Pearl Co., an organization interested in using the craft to recover pearls from deep sea oyster beds in the Bay of Panama. Decompression sickness (the bends), unknown at the time, began to affect the crew in 1869, which led to the abandonment of Explorer in the tidal zone of St. Elmo’s Island (Isla San Telmo) in the Archipielago de las Perlas, Panama

Corrosion of Civil War Era Sub Marine Explorer—Part 1

The Sub Marine Explorer is one of five submersibles (submarines) constructed prior to 1870 that have survived either in museums or as in situ archaeological sites around the world. Since 1869, the wreck of Explorer has emerged at low tide on the beach of Isla San Telmo, Archipiélago de las Perlas, Panama, located ~75 km southwest of Panama City in the Bay of Panama. In 2001, James Delgado visited the site. Locals described the wreck as a World War II-era Japanese midget submarine. Delgado consulted with Richard Wills, an expert on American Civil War submarines, and confirmed that the well-preserved wreck was the Sub Marine Explorer from the Civil War period

A ductility metric for refractory-based multi-principal-element alloys

We propose a quantum-mechanical dimensionless metric, the local$-$lattice distortion (LLD), as a reliable predictor of ductility in refractory multi-principal-element alloys (RMPEAs). The LLD metric is based on electronegativity differences in localized chemical environments and combines atomic$-$scale displacements due to local lattice distortions with a weighted average of valence$-$electron count. To evaluate the effectiveness of this metric, we examined body$-$centered cubic (bcc) refractory alloys that exhibit ductile$-$to$-$brittle behavior. Our findings demonstrate that local$-$charge behavior can be tuned via composition to enhance ductility in RMPEAs. With finite$-$sized cell effects eliminated, the LLD metric accurately predicted the ductility of arbitrary alloys based on tensile$-$elongation experiments. To validate further, we qualitatively evaluated the ductility of two refractory RMPEAs, i.e., NbTaMoW and Mo$_{72}$W$_{13}Ta$_{10}Ti$_{2.5}Zr$_{2.5}, through the observation of crack formation under indentation, again showing excellent agreement with LLD predictions. A comparative study of three refractory alloys provides further insights into the electronic-structure origin of ductility in refractory RMPEAs. This proposed metric enables rapid and accurate assessment of ductility behavior in the vast RMPEA composition space.Comment: 36 pages, 12 figures, 5 Tabl

Penalized Estimating Functions and Variable Selection in Semiparametric Regression Models

We propose a general strategy for variable selection in semiparametric regression models by penalizing appropriate estimating functions. Important applications include semiparametric linear regression with censored responses and semiparametric regression with missing predictors. Unlike the existing penalized maximum likelihood estimators, the proposed penalized estimating functions may not pertain to the derivatives of any objective functions and may be discrete in the regression coefficients. We establish a general asymptotic theory for penalized estimating functions and present suitable numerical algorithms to implement the proposed estimators. In addition, we develop a resampling technique to estimate the variances of the estimated regression coefficients when the asymptotic variances cannot be evaluated directly. Simulation studies demonstrate that the proposed methods perform well in variable selection and variance estimation. We illustrate our methods using data from the Paul Coverdell Stroke Registry

EFFECTS OF MANAGEMENT PRACTICES ON GRASSLAND BIRDS: LESSER PRAIRIE-CHICKEN

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 4,000 published and unpublished papers. A range map is provided to indicate the breeding distribution of Lesser Prairie-Chicken in the United States and southern Canada. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which provides the fundamental components or keys to management for the species. A section on breeding range outlines the current breeding distribution of the species in North America. The suitable habitat section describes the breeding habitat and occasionally microhabitat characteristics of the species, especially those habitats that occur in the Great Plains. Details on habitat and microhabitat requirements often provide clues to how a species will respond to a particular management practice. A table near the end of the account complements the section on suitable habitat, and lists the specific habitat characteristics for the species by individual studies. A special section on prey habitat is included for those predatory species that have more specific prey requirements. The area requirements section provides details on territory and home range sizes, minimum area requirements, and the effects of patch size, edges, and other landscape and habitat features on abundance and productivity. It may be futile to manage a small block of suitable habitat for a species that has minimum area requirements that are larger than the area being managed. The Brown-headed Cowbird (Molothrus ater) is an obligate brood parasite of many grassland birds. The section on cowbird brood parasitism summarizes rates of cowbird parasitism, host responses to parasitism, and factors that influence parasitism, such as nest concealment and host density. The impact of management depends, in part, upon a species’ nesting phenology and biology. The section on breeding-season phenology and site fidelity includes details on spring arrival and fall departure for migratory populations in the Great Plains, peak breeding periods, the tendency to renest after nest failure or success, and the propensity to return to a previous breeding site. The duration and timing of breeding varies among regions and years. Species’ response to management summarizes the current knowledge and major findings in the literature on the effects of different management practices on the species. The section on management recommendations complements the previous section and summarizes specific recommendations for habitat management provided in the literature. If management recommendations differ in different portions of the species’ breeding range, recommendations are given separately by region. The literature cited contains references to published and unpublished literature on the management effects and habitat requirements of the species. This section is not meant to be a complete bibliography; a searchable, annotated bibliography of published and unpublished papers dealing with habitat needs of grassland birds and their responses to habitat management is posted at the Web site mentioned below

Corrosion of Steel Shipwreck in the Marine Environment: USS \u3ci\u3eArizona\u3c/i\u3e—Part 1

The USS Arizona has remained submerged in Pearl Harbor, Hawaii, since the Japanese attack on December 7, 1941. The ship presents a potential hazard from fuel oil still present in the ship’s hull. As an important factor in management decisions, the effect of corrosion after nearly 65 years is being studied to determine the integrity of the ship’s structure. Coupon samples from the hull revealed decreasing corrosion rates from ~1 to 3 mpy (0.03 to 0.08 mm/y) from just below the water surface to the mudline. This is about one-third of that expected in the absence of biofouling or concretion. Methods of determining the corrosion rate, including correlation of chemistry and properties, are discussed

Estimates of Carbon Mitigation Potential from Agricultural and Forestry Activities

Numerous theoretical and empirical studies estimate the greenhouse gas (GHG) mitigation potential of farm and forestry activities, and suggest that the potential for carbon uptake in agricultural soils and forest lands is much greater than current rates. Following a discussion of the estimated current emissions and carbon sequestration by the agricultural and forestry sectors, this report presents a brief overview of the available estimates from USDA and EPA carbon mitigation studies, and then discusses some of the limitations of the available data and modeling results. This report is organized into four parts, including a brief overview of the agriculture and forestry sectors within the broader climate change debate, as well as various data and information on potential for carbon storage and mitigation from farming and forestry activities