1,762 research outputs found

    Henri Temianka Correspondence; (dorr)

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    This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/3487/thumbnail.jp

    A 'p-n' diode with hole and electron-doped lanthanum manganite

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    The hole-doped manganite La0.7Ca0.3MnO3 and the electron-doped manganite La0.7Ce0.3MnO3 undergo an insulator to metal transition at around 250 K, above which both behave as a polaronic semiconductor. We have successfully fabricated an epitaxial trilayer (La0.7Ca0.3MnO3/SrTiO3/La0.7Ce0.3MnO3), where SrTiO3 is an insulator. At room temperature, i.e. in the semiconducting regime, it exhibits asymmetric current-voltage (I-V) characteristics akin to a p-n diode. The observed asymmetry in the I-V characteristics disappears at low temperatures where both the manganite layers are metallic. To the best of our knowledge, this is the first report of such a p-n diode, using the polaronic semiconducting regime of doped manganites.Comment: PostScript text and 2 figures, to be published in Appl. Phys. Lett

    Master agreement task order 2 - Analyses and limited evaluations of payload and landing system structures for the survivable soft landing of instrument payloads

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    Computer programs for analysis and evaluation of payload and landing system structures for soft landing of instrument package

    Migratory Flyways May Affect Population Structure in Double‐Crested Cormorants

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    Double‐crested cormorants (Phalacrocorax auritus) recovered from a demographic bottleneck so well that they are now considered a nuisance species at breeding and wintering grounds across the United States and Canada. Management of this species could be improved by refining genetic population boundaries and assigning individuals to their natal population. Further, recent radio‐telemetry data suggest the existence of Interior and Atlantic migratory flyways, which could reduce gene flow and result in substantial genetic isolation. In this study, we used 1,784 individuals collected across the eastern United States, a large panel of microsatellite markers developed for this species, and individuals banded as chicks and recaptured as adults to explore the effects of migratory flyways on population structure, quantify the genetic effects of demographic bottlenecks, and determine whether individuals could be assigned to their natal population based on genotype. We found evidence for genetic population division only along migratory flyways, no evidence of genetic bottlenecks, and mixed effectiveness of assignment tests. Our population structure findings suggest that gene flow is high across large scales; for example, individuals from New York, Minnesota, and Alabama are all in panmixia. We also found that traditional subspecies ranges may not be valid because \u3e1 subspecies was present in single genetic populations. The lack of evidence for genetic bottlenecks also likely underscores the vagility of this species, suggesting that even during demographic bottlenecks, populations were not isolated from allelic exchange. Finally, the failure of assignment tests to consistently perform is likely due in part to imperfect a priori sampling of Atlantic and Interior chicks and the high vagility of adults. We conclude that the demographic bottleneck is not likely to have reduced genetic diversity, and that assignment tests remain unreliable for this species. We recommend double-crested cormorants be managed by flyway. Further development of genomic resources in this species could improve population subdivision resolution, improve assignment tests, and reveal further information on demographic histories

    Uncertainty of Exploitation Estimates Made from Tag Returns

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    Movement of \u3ci\u3eHypophthalmichthys\u3c/i\u3e DNA in the Illinois River Watershed by the Double-Crested Cormorant (\u3ci\u3ePhalacrocorax auritus\u3c/i\u3e)

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    Paired throat and cloacal swabs, along with feather samples, from nesting Double-crested Cormorants (Phalacrocorax auritus) at two sites in Illinois, USA, were tested for presence of invasive bigheaded carp (Hypophthalmichthys spp.) DNA. We also used DNA from the feather calamus to determine cormorant sex. Throat and cloacal swabs from cormorants at both locations tested positive for DNA from silver carp (H. molitrix), but none tested positive for bighead carp (H. nobilis). Hypophthalmichthys DNA was not detected on feathers. There were no significant differences among positive Hypophthalmichthys DNA detection frequencies between cormorant sexes. To our knowledge, this is the first demonstration of silver carp as part of the Double-crested Cormorant diet in North America. Hypophthalmichthys are major invasive species of concern in this region, the detection of water-borne environmental DNA of Hypophthalmichthys is an important monitoring tool, and the potential movement of DNA via piscivorous birds may have significant implications for interpreting environmental DNA monitoring data

    Effects of Recycled Tyre Steel Fibres on the Compressive, Splitting Tensile and Flexural Strengths of Structural Lightweight Concrete Using Palm Kernel Shells as Partial Replacement of Coarse Aggregates

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    The improper handling and disposal of waste tyres in many African countries is still a serious problem which has caused environmental and health hazards. Like waste tyres, the proper reuse of agricultural wastes, such as palm kernel shells, is also a challenge as the production has increased over the years. In the field of civil engineering, effort have been made to recycle waste tyres and palm kernel shells in concrete production to mitigate some of the environmental problems arising from these wastes. The recycling of such waste for civil engineering applications has been heightened with the development of new technologies. This study was carried out to evaluate and assess the effects of recycled tyre steel fibres and palm kernel shells on the compressive, splitting tensile and flexural strengths of structural lightweight concrete, using recycled tyre steel fibres for reinforcement and palm kernel shells as partial replacement of coarse aggregates. Recycled tyres steel fibres were added in normal-weight concrete at 0.25, 0.50 and 0.75% (Viz., 6, 12 and 18 kg/m3) content and aspect ratio of 20, 40, 60, 80 and 100% to determine the optimal fibres content and aspect ratio. The results show that recycled tyres steel fibres obtained from pyrolysis can improve the compressive and splitting strengths of normal-weight concrete. The optimal fibres content and aspect ratio were used with palm kernel shells at 25, 50, and 75% content to determine the optimal partial replacement of coarse aggregates with palm kernel shells. The maximum compressive and splitting tensile strengths values were obtained at an aspect ratio of 80, palm kernel shell content of 25% and steel content of 0.50%. Normal-weight concrete strength values in flexure were higher than lightweight concrete made with optimal values. Additionally, beams with 25 and 50% content of palm kernel shells with optimal fibre content and aspect ratios qualified as structural lightweight concrete. Keywords: palm kernel shells, recycled tyres steel fibres, waste tyres, lightweight concrete, normal-weight concrete, compressive strength, splitting tensile strength and flexural strength. DOI: 10.7176/CER/11-6-06 Publication date:July 31st 201

    Predicting consistent foraging ecologies of migrating waterbirds: Using stable isotope and parasite measurements as indicators of landscape use

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    The emergence of novel human pathogens is frequently linked with zoonotic events and human-wildlife interactions that promote disease transmission. Consequently, surveillance of wildlife populations for candidate diseases that could spread to humans is beneficial, but requires widespread collections of numerous samples. A legitimate means to acquire large sample sizes of waterfowl is through cooperation between researchers and hunters, who also work in concert with natural resource managers, landowners, and agricultural entities -e.g., aquaculture facilities. In addition to understanding the occurrence and spread of parasites and pathogens by birds, these samples can be used to answer questions about the ecology of various waterbird species. Body mass and morphometric data on hunter-donated specimen are useful for understanding bird condition and other dynamics of birds; however, when breast meat is removed prior to the acquisition of specimen weight, samples might not be as desirable. Here, we evaluate the utility of data obtained from a bird species that might be targeted by hunters and subsequently used to learn about their disease dynamics. Lesser Scaup (Aythya affinis) collected at aquaculture facilities were assessed for their stable isotope concentrations and parasites communities to learn about the birds’ foraging ecology. Discriminant analyses designed to classify birds by the aquaculture pond type from which they were collected included isotope data, Principal Components derived from parasite community data of 7 types, and birds’ body mass. We compared these to Double-crested Cormorants (Nannopterum auritum) feeding on catfish and found the two waterbird species exhibited different infracommunities of parasites Furthermore, some scaup demonstrated fish aquaculture pond type fidelity. Bird body mass was an important metric to include in analytical models when all parasite datatypes were not available. However, the combination of stable isotope concentrations and parasite infracommunity data (that includes prevalence, abundance, volume, and energy use) in models resulted in host ecology differentiation equal or better than models where bird body mass was included. Hunter-derived samples should be encouraged as a means for sample acquisition and be considered as an approach for aquaculture-wildlife conflict management as the information that can be obtained through these samples is multifaceted
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