797 research outputs found

    The Yosemite Butterflies: Color Plates

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    This compilation of butterfly illustrations for the Yosemite region is intended primarily as a supplement to the text publication on Yosemite butterflies (Davenport, 2004, and Davenport, 2007, 2nd edition). Taxonomic interpretations and names follow these documents. Common names and authors of the scientific names are given in the text publication. This color plates publication also functions as a stand-alone document for naturalists and lepidopterists with need for reference illustrations only. Butterflies were selected from Ken Davenport’s private collection to illustrate most species and subspecies for the Yosemite region. If good quality specimens were available from within the region, we often used those. Most of the photography was done by Charles Grisham. In other cases Jim Brock, Howard Grisham, Norbert Kondla, Richard Meyer, John Pasko, Andrew Warren, Michael Leski, and Crispin Guppy provided needed specimens or photographs. Most of the illustrated specimens were photographed under indirect natural light to maintain color fidelity. Most were also photographed using the ‘glass plate’ method to produce shadow-free images. Digital cameras were used for all illustrations. Norbert Kondla edited the raw images and assembled them into life size plate format. Paint Shop Pro was used for image editing and Microsoft Word was used for plate assembly. Specimen localities given are mostly from within California, United States. All specimens illustrated were collected by Kenneth Davenport unless otherwise noted

    Isolation and primary cultures of human intrahepatic bile ductular epithelium

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    A technique for the isolation of human intrahepatic bile ductular epithelium, and the establishment of primary cultures using a serum- and growth-factor-supplemented medium combined with a connective tissue substrata is described. Initial cell isolates and monolayer cultures display phenotypic characteristics of biliary epithelial cells (low molecular weight prekeratin positive; albumin, alphafetoprotein, and Factor VIII-related antigen negative). Ultrastructural features of the cultured cells show cell polarization with surface microvilli, numerous interepithelial junctional complexes and cytoplasmic intermediate prekeratin filaments. © 1988 Tissue Culture Association, Inc

    Proof-of-Concept of a Networked Validation Environment for Distributed Air/Ground NextGen Concepts

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    The National Airspace System (NAS) must be improved to increase capacity, reduce flight delays, and minimize environmental impacts of air travel. NASA has been tasked with aiding the Federal Aviation Administration (FAA) in NAS modernization. Automatic Dependent Surveillance-Broadcast (ADS-B) is an enabling technology that is fundamental to realization of the Next Generation Air Transportation System (NextGen). Despite the 2020 FAA mandate requiring ADS-B Out equipage, airspace users are lacking incentives to equip with the requisite ADS-B avionics. A need exists to validate in flight tests advanced concepts of operation (ConOps) that rely on ADS-B and other data links without requiring costly equipage. A potential solution is presented in this paper. It is possible to emulate future data link capabilities using the existing in-flight Internet and reduced-cost test equipment. To establish proof-of-concept, a high-fidelity traffic operations simulation was modified to include a module that simulated Internet transmission of ADS-B messages. An advanced NASA ConOp, Flight Deck Interval Management (FIM), was used to evaluate technical feasibility. A preliminary assessment of the effects of latency and dropout rate on FIM was performed. Flight hardware that would be used by proposed test environment was connected to the simulation so that data transfer from aircraft systems to test equipment could be verified. The results indicate that the FIM ConOp, and therefore, many other advanced ConOps with equal or lesser response characteristics and data requirements, can be evaluated in flight using the proposed concept

    Phenotypic and karyotypic changes induced in cultured rat hepatic epithelial cells that express the "oval" cell phenotype by exposure to N-methyl-N'-nitro-N-nitrosoguanidine.

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    A diploid population of cultured rat hepatic epithelial cells that expresses the "oval" cell phenotype was exposed briefly and repetitively to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and the effect on more than 20 phenotypic properties was evaluated during the neoplastic transformation of the population. MNNG treatments of this hepatic epithelial cell population resulted in a progressively increasing phenotypic alteration and heterogeneity including changes in specific activities of several cellular enzymes and expression of isozymes, synthetic functions, and various in vitro growth properties. Changes in phenotypic expression were clustered episodically and were associated with major karyotypic changes. The development of increasing phenotypic heterogeneity preceding and accompanying tumorigenicity in cultured liver epithelial cells in vitro and the specific phenotypes that occur resemble superficially the pattern of phenotypic changes that occur in hepatocytes during chemical hepatocarcinogenesis in vivo. The results of this study provide the basis for future investigations to further elucidate the mechanistic and linkage relationship between specific pretumorigenic and paratumorigenic phenotypes and tumorigenicity

    The relative contribution of climate to changes in lesser prairie-chicken abundance

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    Citation: Ross, B. E., Haukos, D., Hagen, C., & Pitman, J. (2016). The relative contribution of climate to changes in lesser prairie-chicken abundance. Ecosphere, 7(6), 11. doi:10.1002/ecs2.1323Managing for species using current weather patterns fails to incorporate the uncertainty associated with future climatic conditions; without incorporating potential changes in climate into conservation strategies, management and conservation efforts may fall short or waste valuable resources. Understanding the effects of climate change on species in the Great Plains of North America is especially important, as this region is projected to experience an increased magnitude of climate change. Of particular ecological and conservation interest is the lesser prairie-chicken (Tympanuchus pallidicinctus), which was listed as "threatened" under the U.S. Endangered Species Act in May 2014. We used Bayesian hierarchical models to quantify the effects of extreme climatic events (extreme values of the Palmer Drought Severity Index [PDSI]) relative to intermediate (changes in El Nino Southern Oscillation) and long-term climate variability (changes in the Pacific Decadal Oscillation) on trends in lesser prairie-chicken abundance from 1981 to 2014. Our results indicate that lesser prairie-chicken abundance on leks responded to environmental conditions of the year previous by positively responding to wet springs (high PDSI) and negatively to years with hot, dry summers (low PDSI), but had little response to variation in the El Nino Southern Oscillation and the Pacific Decadal Oscillation. Additionally, greater variation in abundance on leks was explained by variation in site relative to broad-scale climatic indices. Consequently, lesser prairie-chicken abundance on leks in Kansas is more strongly influenced by extreme drought events during summer than other climatic conditions, which may have negative consequences for the population as drought conditions intensify throughout the Great Plains

    High current source of He −

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    A negative helium ion beam of 70 mA at 10.5 kV has been produced by charge exchange in sodium. The production is studied as a function of sodium line density, beam energy and background helium gas density. The characteristics of this high current He{sup -} source are analyzed to determine the design requirements for He{sup -} beam generation in the range of tens to hundred of milliamperes

    Development of a qPCR for Leifsonia xyli subsp. xyli and quantification of the effects of heat treatment of sugarcane cuttings on Lxx

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    The main control practice of Leifsonia xyli subsp. xyli (Lxx) in sugarcane is to heat-treat cane cuttings used as planting material in an attempt to eradicate the bacterium. A real time quantitative PCR (qPCR) protocol specific for Lxx was developed to assess the effectiveness of this practice. Primers were designed from the sequence of an Lxx-specific gene and detected as few as 10−5 ng of Lxx DNA in 100 ng of plant DNA. Two experiments were conducted to quantify Lxx titers in plants of the varieties SP80-3280 and SP70-3370 originated from cuttings treated or not by immersion in hot water at 52 °C for 30 min. In the first experiment, cuttings were collected from plant canes with low Lxx titers whereas in the second they were collected from first-ratoon canes with higher titers. Lxx was quantified in leaves by qPCR 90 days after planting and was detected in 50–90% of the plants at variable titers, indicating that the 52 °C hot water treatment for 30 min was not effective in eradicating Lxx from all plants. However, in the second experiment the bacterial population was reduced, as the median number of Lxx cells was lower compared to the non-treated control. In the case of SP70-3370, the treatment also reduced the number of Lxx-infected plants considering the pooled data of the two experiments. The results indicated that although the 52 °C hot water treatment for 30 min did not completely eliminate Lxx, it can be used to reduce the pathogen population in plants propagated from canes with high Lxx titer

    Mouse model of liver ischemia and reperfusion injury: method for studying reactive oxygen and nitrogen metabolites in vivo

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    The mouse model of liver ischemia and reperfusion injury has proven to be valuable for our understanding of the role that reactive oxygen and nitrogen metabolites play in postischemic tissue injury. This methods paper provides a detailed protocol for inducing partial liver ischemia followed by reperfusion. Liver ischemia is induced in anesthetized mice by cross-clamping the hepatic artery and portal vein for varying lengths of time resulting in deprivation of blood flow to approximately of 70% of the liver. Restoration of blood flow to the ischemic lobes enhances superoxide production concomitant with a rapid and marked decrease in the bioavailability of nitric oxide resulting in alterations in the redox state of the liver in favor of a more oxidative environment. This hepatocellular oxidative stress induces the activation of oxidant-sensitive transcription factors followed by the upregulation of pro-inflammatory cytokines and mediators that ultimately lead to liver injury. This model can be induced in any strain or sex of mouse and requires 1-2 months of practice to become proficient in the surgery and animal manipulation. The role of different reactive metabolites of oxygen and nitrogen may be evaluated using genetically-engineered mice as well as selective molecular, cellular and/or pharmacological agents

    Damage to extreme-ultraviolet Sc/Si multilayer mirrors exposed to intense 46.9-nm laser pulses

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    Includes bibliographical references (page 622).The damage threshold and damage mechanism of extreme-ultraviolet Sc/Si multilayer mirror coatings are investigated with focused nanosecond pulses at 46.9-nm radiation from a compact capillary-discharge laser. Damage threshold fluences of ~0.08 J/cm2 are measured for coatings deposited on both borosilicate glass and Si substrates. The use of scanning and transmission electron microscopy and small-angle x-ray diffraction techniques reveals the thermal nature of the damage mechanism. The results are relevant to the use of newly developed high-flux extreme-ultraviolet sources in applications
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