200 research outputs found

    Rapid Effective Trace-Back Capability Value in Reducing the Cost of a Foot and Mouth Disease Event

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    This study evaluates how the availability of animal tracing affects the cost of a hypothetical Foot and Mouth Disease (FMD) outbreak in the Texas High Plains using alternative tracing scenarios. To accomplish this objective, the AusSpread epidemic disease spread model (Ward et al., 2006) is used to simulate a High Plains FMD outbreak under different animal tracing possibilities. A simple economic costing module (Elbakidze, 2008) is used to determine the savings in terms of animal disease mitigation costs from rapid, effective trace-back. The savings from increased traceability are then be compared to the cost of a functional National Animal Identification System (NAIS). Initial results indicate that rapid, effective tracing reduces the overall cost of disease outbreaks and that the benefits per animal in terms of reduced cost of an outbreak more than outweigh the annualized cost per animal of implementing a NAIS. A value of time related to controlling an outbreak is estimated to have increased benefits from an identification system that incorporates a rapid response capability. We also find the level of benefits vary depending on the location of initial infection and whether or not welfare slaughter occurs.Traceability, Foot and Mouth Disease, Economics, Agricultural and Food Policy, Livestock Production/Industries,

    Sawflies (Hymenoptera, Symphyta) Newly Recorded from Washington State

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    Examination of museum specimens, unpublished collection data, and field surveys conducted between 2010 and 2014 resulted in records for 22 species of sawflies new to Washington State, seven of which are likely to be pest problems in ornamental landscapes. These data highlight the continued range expansion of exotic species across North America. These new records also indicate that our collective knowledge of Pacific Northwest arthropod biodiversity and biogeography is underdeveloped, even for a relatively well known and species-poor group of insects. Notable gaps in the knowledge of Washington State’s Symphyta remain for the Olympic Peninsula, the Cascade Mountain Range, and the arid interior of the state. Washington’s shrub-steppe appears to be particularly poorly surveyed for sawflies

    Sawflies (Hymenoptera, Symphyta) Newly Recorded from Washington State

    Get PDF
    Examination of museum specimens, unpublished collection data, and field surveys conducted between 2010 and 2014 resulted in records for 22 species of sawflies new to Washington State, seven of which are likely to be pest problems in ornamental landscapes. These data highlight the continued range expansion of exotic species across North America. These new records also indicate that our collective knowledge of Pacific Northwest arthropod biodiversity and biogeography is underdeveloped, even for a relatively well known and species-poor group of insects. Notable gaps in the knowledge of Washington State’s Symphyta remain for the Olympic Peninsula, the Cascade Mountain Range, and the arid interior of the state. Washington’s shrub-steppe appears to be particularly poorly surveyed for sawflies

    A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks

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    We present a CARMA 1.3 mm continuum survey toward 9 Class 0 protostars in the Perseus molecular cloud at \sim0.3^{\prime\prime} (70 AU) resolution. This study approximately doubles the number of Class 0 protostars observed with spatial resolutions << 100 AU at millimeter wavelengths, enabling the presence of protostellar disks and proto-binary systems to be probed. We detect flattened structures with radii >> 100 AU around 2 sources (L1448 IRS2 and Per-emb-14) and these sources may be strong disk candidates. Marginally-resolved structures with position angles within 30^{\circ} of perpendicular to the outflow are found toward 3 protostars (L1448 IRS3C, IRAS 03282+3035, and L1448C) and are considered disk candidates. Two others (L1448 IRS3B and IRAS 03292+3039) have resolved structure, possibly indicative of massive inner envelopes or disks; L1448 IRS3B also has a companion separated by 0.9^{\prime\prime} (\sim210 AU). IC348-MMS does not have well-resolved structure and the candidate first hydrostatic core L1451-MMS is marginally resolved on 1^{\prime\prime} scales. The strong disk candidate sources were followed-up with C18^{18}O (J=21J=2\rightarrow1) observations, detecting velocity gradients consistent with rotation, but it is unclear if the rotation is Keplerian. We compare the observed visibility amplitudes to radiative transfer models, finding that visibility amplitude ratios suggest a compact component (possibly a disk) is necessary for 5 of 9 Class 0 sources; envelopes alone may explain the other 4 systems. We conclude that there is evidence for the formation of large disks in the Class 0 phase with a range of radii and masses dependent upon their initial formation conditions.Comment: Accepted to ApJ, 58 pages, 19 Figures, 5 Table

    Confirmation of a recent bipolar ejection in the very young hierarchical multiple system IRAS 16293-2422

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    We present and analyze two new high-resolution (approx 0.3 arcsec), high-sensitivity (approx 50 uJy beam-1) Very Large Array 3.6 cm observations of IRAS 16293-2422 obtained in 2007 August and 2008 December. The components A2alpha and A2beta recently detected in this system are still present, and have moved roughly symmetrically away from source A2 at a projected velocity of 30-80 km s-1. This confirms that A2alpha and A2beta were formed as a consequence of a very recent bipolar ejection from A2. Powerful bipolar ejections have long been known to occur in low-mass young stars, but this is -to our knowledge-- the first time that such a dramatic one is observed from its very beginning. Under the reasonable assumption that the flux detected at radio wavelengths is optically thin free-free emission, one can estimate the mass of each ejecta to be of the order of 10^-8 Msun. If the ejecta were created as a consequence of an episode of enhanced mass loss accompanied by an increase in accretion onto the protostar, then the total luminosity of IRAS 16293-2422 ought to have increased by 10-60% over the course of at least several months. Between A2alpha and A2beta, component A2 has reappeared, and the relative position angle between A2 and A1 is found to have increased significantly since 2003-2005. This strongly suggests that A1 is a protostar rather than a shock feature, and that the A1/A2 pair is a tight binary system. Including component B, IRAS 16293-2422 therefore appears to be a very young hierarchical multiple system.Comment: Accepted for publication in The Astrophysical Journa

    Spitzer spectral line mapping of protostellar outflows: I. Basic data and outflow energetics

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    We report the results of spectroscopic mapping observations carried out toward protostellar outflows in the BHR71, L1157, L1448, NGC 2071, and VLA 1623 molecular regions using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope. These observations, covering the 5.2 - 37 micron spectral region, provide detailed maps of the 8 lowest pure rotational lines of molecular hydrogen and of the [SI] 25.25 micron and [FeII] 26.0 micron fine structure lines. The molecular hydrogen lines, believed to account for a large fraction of the radiative cooling from warm molecular gas that has been heated by a non-dissociative shock, allow the energetics of the outflows to be elucidated. Within the regions mapped towards these 5 outflow sources, total H2 luminosities ranging from 0.02 to 0.75 L(solar) were inferred for the sum of the 8 lowest pure rotational transitions. By contrast, the much weaker [FeII] 26.0 micron fine structure transition traces faster, dissociative shocks; here, only a small fraction of the fast shock luminosity emerges as line radiation that can be detected with Spitzer/IRS.Comment: 38 pages including 17 figures. Accepted for publication in Ap

    Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

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    The Single Aperture Far-InfraRed (SAFIR) Observatory's science goals are driven by the fact that the earliest stages of almost all phenomena in the universe are shrouded in absorption by and emission from cool dust and gas that emits strongly in the far-infrared and submillimeter. Over the past several years, there has been an increasing recognition of the critical importance of this spectral region to addressing fundamental astrophysical problems, ranging from cosmological questions to understanding how our own Solar System came into being. The development of large, far-infrared telescopes in space has become more feasible with the combination of developments for the James Webb Space Telescope and of enabling breakthroughs in detector technology. We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature (<4K) and instrument complement would be optimized to reach the natural sky confusion limit in the far-infrared with diffraction-limited peformance down to at least 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of Spitzer or Herschel, with finer angular resolution, enabling imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology, detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays.Comment: 36 page
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