4,024 research outputs found

    Unmanned Aerial Power line Surveillance Drone

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    The purpose of our project is to provide power line workers and linemen with a safe way to inspect the power lines. Our Aircraft is an UAV that is capable of surveying 200 linear miles in a normal working shift. The aircraft will be launched/landed and operated from an F-150 pickup truck with a facilitated launch mechanism attached. The aircraft must maintain an altitude of 150-400 ft. It will be recovered via net that will extend from the truck as the plane comes in for a landing, This will eliminate the need for landing gear. The goal for this project was to create a long range stable aircraft that weighed less than 55 pounds

    Alloparental behaviour and long-term costs of mothers tolerating other members of the group in a plurally breeding mammal

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    Cooperative-breeding studies tend to focus on a few alloparental behaviours in highly cooperative species exhibiting high reproductive skew and the associated short-term, but less frequently long-term, fitness costs. We analysed a suite of alloparental behaviours (assessed via filming) in a kin-structured, high-density population of plurally breeding European badgers, Meles meles, which are not highly cooperative. Group members, other than mothers, performed alloparental behaviour; however, this was not correlated with their relatedness to within-group young. Furthermore, mothers babysat, allogroomed cubs without reciprocation, and allomarked cubs more than other members of the group (controlling for observation time). For welfare reasons, we could not individually mark cubs; however, the number observed pre-independence never exceeded that trapped. All 24 trapped cubs, in three filmed groups, were assigned both parents using 22 microsatellites. Mothers may breed cooperatively, as the time they babysat their assigned, or a larger, litter size did not differ. Furthermore, two mothers probably allonursed, as they suckled more cubs than their assigned litter size. An 18-year genetic pedigree, however, detected no short-term (litter size; maternal survival to the following year) or long-term (offspring breeding probability; offspring lifetime breeding success) fitness benefits with more within-group mothers or other members of the group. Rather, the number of other members of the group (excluding mothers) correlated negatively with long-term fitness. Mothers may tolerate other members of the group, as nonbreeders undertook more digging. Our study highlights that alloparental care varies on a continuum from that seen in this high-density badger population, where alloparenting behaviour is minimal, through to species where alloparental care is common and provides fitness benefits. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved

    Using climate reanalysis data in conjunction with multi-temporal satellite thermal imagery to derive supraglacial debris thickness changes from energy balance modelling

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    Surface energy-balance models are commonly used in conjunction with satellite thermal imagery to estimate supraglacial debris thickness. Removing the need for local meteorological data in the debris thickness estimation workflow could improve the versatility and spatiotemporal application of debris thickness estimation. We evaluate the use of regional reanalysis data to derive debris thickness for two mountain glaciers using a surface energy-balance model. Results forced using ERA-5 agree with AWS-derived estimates to within 0.01 ± 0.05 m for Miage Glacier, Italy, and 0.01 ± 0.02 m for Khumbu Glacier, Nepal. ERA-5 data were then used to estimate spatiotemporal changes in debris thickness over a ~20-year period for Miage Glacier, Khumbu Glacier and Haut Glacier d'Arolla, Switzerland. We observe significant increases in debris thickness at the terminus for Haut Glacier d'Arolla and at the margins of the expanding debris cover at all glaciers. While simulated debris thickness was underestimated compared to point measurements in areas of thick debris, our approach can reconstruct glacier-scale debris thickness distribution and its temporal evolution over multiple decades. We find significant changes in debris thickness over areas of thin debris, areas susceptible to high ablation rates, where current knowledge of debris evolution is limited

    Eosinophil Lipid Bodies: Specific, Inducible Intracellular Sites for Enhanced Eicosanoid Formation

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    The specific intracellular sites at which enzymes act to generate arachidonate-derived eicosanoid mediators of inflammation are uncertain. We evaluated the formation and function of cytoplasmic lipid bodies. Lipid body formation in eosinophils was a rapidly (<1 h) inducible response which was platelet-activating factor (PAF) receptor–mediated, involved signaling through protein kinase C, and required new protein synthesis. In intact and enucleated eosinophils, the PAF-induced increases in lipid body numbers correlated with enhanced production of both lipoxygenase- and cyclooxygenase-derived eicosanoids. All principal eosinophil eicosanoid-forming enzymes, 5-lipoxygenase, leukotriene C4 synthase, and cyclooxygenase, were immunolocalized to native as well as newly induced lipid bodies in intact and enucleated eosinophils. Thus, lipid bodies are structurally distinct, inducible, nonnuclear sites for enhanced synthesis of paracrine eicosanoid mediators of inflammation

    An optimized method for detecting gamma-H2AX in blood cells reveals a significant interindividual variation in the gamma-H2AX response among humans

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    Phosphorylation of histone H2AX on serine 139 (gamma-H2AX, γH2AX) occurs at sites flanking DNA double-strand breaks (DSBs) and can provide a measure of the number of DSBs within a cell. Here we describe a rapid and simple flow-cytometry-based method, optimized to measure gamma-H2AX in non-fixed peripheral blood cells. No DSB induced signal was observed in H2AX−/− cells indicating that our FACS method specifically recognized gamma-H2AX accumulation. The gamma-H2AX assay was capable of detecting DNA damage at levels 100-fold below the detection limit of the alkaline comet assay. The gamma-H2AX signal was quantitative with a linear increase of the gamma-H2AX signal over two orders of magnitude. We found that all nucleated blood cell types examined, including the short-lived neutrophils induce gamma-H2AX in response to DSBs. Interindividual difference in the gamma-H2AX signal in response to ionizing radiation and the DSB-inducing drug calicheamicin was almost 2-fold in blood cells from patients, indicating that the amount of gamma-H2AX produced in response to a given dose of radiation varies significantly in the human population. This simple method could be used to monitor response to radiation or DNA-damaging drugs

    Postreproductive lifespans are rare in mammals

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    A species has a post‐reproductive stage if, like humans, a female entering the adult population can expect to live a substantial proportion of their life after their last reproductive event. However, it is conceptually and statistically challenging to distinguish these true post‐reproductive stages from the usual processes of senescence, which can result in females occasionally surviving past their last reproductive event. Hence, despite considerable interest, the taxonomic prevalence of post‐reproductive stages remains unclear and debated. In this study we use life tables constructed from published data on wild populations of mammals, and statistical measures of post‐reproductive lifespans, to distinguish true post‐reproductive stages from artefacts of senescence and demography in 52 species. We find post‐reproductive stages are rare in mammals and are limited to humans and a few species of toothed whales. By resolving this long‐standing debate, we hope to provide clarity for researchers in the field of evolutionary biology and a solid foundation for further studies investigating the evolution and adaptive significance of this unusual life history trait
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