92 research outputs found

    The Use of Eurasian Dogs to Protect Sheep from Predators in North America: A Summary of Research at the U.S. Sheep Experiment Station

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    The authors thank the sheep producers who cooperated in the study. R. Harman, R. VanHorn, S. Ecret, K. Havelock, J. Geiser, W. Bowers, G. Pendleton, D. Johnson, and C. Schwartz helped with the care and evaluation of the dogs. In the search for methods to reduce coyote (Canis latrans) predation on sheep, livestock guarding dogs have been found to be a relatively successful technique in a variety of conditions including open rangeland (Green and Woodruff in press) and fenced pastures (Linhart et al. 1979, McGrew and Bakesley 1982, Pfeifer and Goos 1982, Green et al. In Press a). Eurasian dogs (Coppinger and Coppinger 1980b) and mongrel dogs (Black 1981) reared from puppyhood with sheep become attentive to the flock, generally remain with sheep, and subsequently help to reduce predation (Coppinger et al. 1983)

    DO LIVESTOCK GUARDING DOGS LOSE THEIR EFFECTIVENESS OVER TIME?

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    Information about the effectiveness of livestock guarding dogs for reducing coyote predation on sheep was gathered from livestock producers in the Animal Damage Control Livestock Guarding Dog Program and in Colorado. Eighty-two percent of the producers contacted reported that the performance of their dogs remained the same or improved during 1993 compared with previous years. Eighteen percent of the producers reported a decrease in their dog\u27s effectiveness, but most still felt the dogs were a benefit to their livestock operation. Most producers who noted a decrease in effectiveness attributed it to an apparent increase in the number of coyotes and/or an increase in their predatory activities on livestock

    SALMON POISONING DISEASE: RESEARCH ON A POTENTIAL METHOD OF LETHAL CONTROL FOR COYOTES

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    Salmon poisoning disease (SPD) was tested as a potential method of lethal control for coyotes (Canis latrans). Fresh fish containing the agents for SPD was fed to 72 captive adult coyotes. Coho (Oncorhunchus kisutch) and steel head salmon (Salmo gairdneri) from Oregon hatcheries were the principal species of fish used. Coyotes that ate the fish developed observable signs of SPD in a mean of 8 days. The overall rate of mortality was 50%, and death occurred in a mean of 20 days from consuming fish. Coyotes that died from SPD lost a mean of 32% of their body weight during the course of the disease. Other coyotes were fed preserved fish samples or administered oral or intraperitoneal treatments of lymph node matter from coyotes that died from SPD. In light of the relatively low rate of mortality observed, feeding coyotes fish to cause death from SPD appears to be a method of questionable value for controlling numbers of adult coyotes in areas of livestock production unless fish with a highly virulent strain of the SPD agent can be obtained

    Simultaneous Exoplanet Characterization and deep wide-field imaging with a diffractive pupil telescope

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    High-precision astrometry can identify exoplanets and measure their orbits and masses, while coronagraphic imaging enables detailed characterization of their physical properties and atmospheric compositions through spectroscopy. In a previous paper, we showed that a diffractive pupil telescope (DPT) in space can enable sub-microarcsecond accuracy astrometric measurements from wide-field images by creating faint but sharp diffraction spikes around the bright target star. The DPT allows simultaneous astrometric measurement and coronagraphic imaging, and we discuss and quantify in this paper the scientific benefits of this combination for exoplanet science investigations: identification of exoplanets with increased sensitivity and robustness, and ability to measure planetary masses to high accuracy. We show how using both measurements to identify planets and measure their masses offers greater sensitivity and provides more reliable measurements than possible with separate missions, and therefore results in a large gain in mission efficiency. The combined measurements reliably identify potentially habitable planets in multiple systems with a few observations, while astrometry or imaging alone would require many measurements over a long time baseline. In addition, the combined measurement allows direct determination of stellar masses to percent-level accuracy, using planets as test particles. We also show that the DPT maintains the full sensitivity of the telescope for deep wide-field imaging, and is therefore compatible with simultaneous scientific observations unrelated to exoplanets. We conclude that astrometry, coronagraphy, and deep wide-field imaging can be performed simultaneously on a single telescope without significant negative impact on the performance of any of the three techniques.Comment: 15 pages, 6 figures. This second paper, following the paper describing the diffractive pupil telescope (DPT) astrometric technique, shows how simultaneous astrometry and coronagraphy observations, enabled by the DPT concept, constrain the orbital parameters and mass of exoplanet

    Design of the Subpopulations and Intermediate Outcome Measures in COPD (SPIROMICS) AIR Study.

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    IntroductionPopulation-based epidemiological evidence suggests that exposure to ambient air pollutants increases hospitalisations and mortality from chronic obstructive pulmonary disease (COPD), but less is known about the impact of exposure to air pollutants on patient-reported outcomes, morbidity and progression of COPD.Methods and analysisThe Subpopulations and Intermediate Outcome Measures in COPD (SPIROMICS) Air Pollution Study (SPIROMICS AIR) was initiated in 2013 to investigate the relation between individual-level estimates of short-term and long-term air pollution exposures, day-to-day symptom variability and disease progression in individuals with COPD. SPIROMICS AIR builds on a multicentre study of smokers with COPD, supplementing it with state-of-the-art air pollution exposure assessments of fine particulate matter, oxides of nitrogen, ozone, sulfur dioxide and black carbon. In the parent study, approximately 3000 smokers with and without airflow obstruction are being followed for up to 3 years for the identification of intermediate biomarkers which predict disease progression. Subcohorts undergo daily symptom monitoring using comprehensive daily diaries. The air monitoring and modelling methods employed in SPIROMICS AIR will provide estimates of individual exposure that incorporate residence-specific infiltration characteristics and participant-specific time-activity patterns. The overarching study aim is to understand the health effects of short-term and long-term exposures to air pollution on COPD morbidity, including exacerbation risk, patient-reported outcomes and disease progression.Ethics and disseminationThe institutional review boards of all the participating institutions approved the study protocols. The results of the trial will be presented at national and international meetings and published in peer-reviewed journals
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