1,047 research outputs found

    On optimizing the treatment of exchange perturbations

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    A method using the zeroth plus first order wave functions, obtained by optimizing the basic equation used in exchange perturbation treatments, is utilized in an attempt to determine the exact energy and wave function in the exchange process. Attempts to determine the first order perturbation solution by optimizing the sum of the first and second order energies were unsuccessful

    Comparison of Primas and Rayleigh- Schrodinger perturbation theories

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    Primas and Rayleigh-Schrodinger formulations of perturbation theory compare

    Rabies Surveillance Identifies Potential Risk Corridors and Enables Management Evaluation

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    Intensive efforts are being made to eliminate the raccoon variant of rabies virus (RABV) from the eastern United States and Canada. The United States Department of Agriculture (USDA) Wildlife Services National Rabies Management Program has implemented enhanced rabies surveillance (ERS) to improve case detection across the extent of the raccoon oral rabies vaccination (ORV) management area. We evaluated ERS and public health surveillance data from 2006 to 2017 in three northeastern USA states using a dynamic occupancy modeling approach. Our objectives were to examine potential risk corridors for RABV incursion from the U.S. into Canada, evaluate the effectiveness of ORV management strategies, and identify surveillance gaps. ORV management has resulted in a decrease in RABV cases over time within vaccination zones (from occupancy (ψ) of 0.60 standard error (SE) = 0.03 in the spring of 2006 to ψ of 0.33 SE = 0.10 in the spring 2017). RABV cases also reduced in the enzootic area (from ψ of 0.60 SE = 0.03 in the spring of 2006 to ψ of 0.45 SE = 0.05 in the spring 2017). Although RABV occurrence was related to habitat type, greater impacts were associated with ORV and trap–vaccinate–release (TVR) campaigns, in addition to seasonal and yearly trends. Reductions in RABV occupancy were more pronounced in areas treated with Ontario Rabies Vaccine Bait (ONRAB) compared to RABORAL V-RG®. Our approach tracked changes in RABV occurrence across space and time, identified risk corridors for potential incursions into Canada, and highlighted surveillance gaps, while evaluating the impacts of management actions. Using this approach, we are able to provide guidance for future RABV management

    A sensitive search for predicted methanol maser transitions with the Australia telescope compact array

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    We have used theAustralia Telescope Compact Array to search for a number of centimetrewavelengthmethanol transitions which are predicted to show weak maser emission towards star formation regions. Sensitive, high spatial, and spectral resolution observations towards four high-mass star formation regions which show emission in a large number of class II methanol maser transitions did not result in any detections. From these observations, we are able to place an upper limit of 1 300 K on the brightness temperature of any emission from the 31A+-31A-, 17-2-18-3 E (vt = 1), 124-133 A-, 124-133 A+, and 41A+-41A- transitions of methanol in these sources on angular scales of 2 arcsec. This upper limit is consistent with current models for class II methanol masers in high-mass star formation regions and better constraints than those provided here will likely require observations with next-generation radio telescopes. © Astronomical Society of Australia 2016

    SWIRP (Submm-Wave and Long Wave InfraRed Polarimeter); Development and Characterization of a Sub-Mm Polarimeter for Ice Cloud Investigations

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    A major source of uncertainty in climate models is the presence, shape and distribution of ice particles in the uppermost layers of the clouds. The effects of this component are poorly constrained, turning ice particles into an almost-free variable in many climate models.NASA-GSFC is developing a new instrument aimed at measuring the size and shape of ice particles. The instrument consists of two sub-mm polarimeters (at 220 and 670 GHz) coupled with a long-wave infrared polarimeter at 10 micron. Each polarimeter has identical V-pol and H-pol channels; the axes of polarization are defined geometrically by the orientation of the waveguide elements, and the purity has been measured in the lab. The instrument is configured as a conical scanner, suitable for deployment as a payload on a small satellite or on a high-altitude sub-orbital platform. From a 400 km orbit, the instrument has a 3dB spatial resolution of 20 (10) km at 220 (670) GHz and a swath of 600 km over 180 degrees of view.The BAPTA (Bearing And Power Transfer Assembly) carries heritage from the SSMIS design, now in its 22nd year of on-orbit operation, but with a much reduced SWaP (Size Weight and Power) footprint, suitable for a small satellite.The main components of the instrument have been fabricated and are undergoing final testing prior to their integration as a single unit. The sub-mm channels have dedicated secondary reflectors which illuminate a shared primary reflector. The receiving units are placed behind the focal point of the optical arrangement, so that all beams equally illuminate the primary reflector and are almost co-located on the ground (within a single 220 GHz footprint). Primary and secondary beam patterns have been measured and verified to match the as-designed expectations. A Zytex (TM) window is deployed to protect the secondary reflectors and the feed horns from debris and other contaminants, and to reduce the heat load from the active (hot) IR calibration unit. The insertion loss of Zytex has been measured and is accounted in the calibration equation of the sub-mm channels.The radiometric performance of the sub-mm receivers has been characterized in the lab and under operational conditions of temperature and pressure.This paper discusses the design constraints on the sub-mm components, details of the scientific goals and their flowdown, and describes the characterization of the polarimeters. Options to optimize the layout and distribution of the masses within the assembly, with the goal of making the instrument even more compact and fully-compatible with cubesat-class satellites will be presented

    Mitigation of Double-crested Cormorant Impacts on Lake Ontario: From Planning and Practice to Product Delivery

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    The New York State Department of Environmental Conservation initiated a Double-crested Cormorant (Phalacrocorax auritus) control program in the eastern basin of Lake Ontario to mitigate cormorant impacts in 1999. Key objectives included improving the quality of Smallmouth Bass (Micropterus dolomieu) and other fisheries, restoring the structure and function of the warmwater fish community and reducing cormorant impacts to nesting habitats of other colonial waterbird species. In eight years of intensive control, cormorant numbers declined, with a corresponding reduction in estimated fish consumption. Diversity and numbers of co-occurring waterbirds either increased or have not been shown to be negatively impacted by management. Woody vegetation favorable to Black-crowned Night-Herons (Nycticorax nycticorax) has been maintained. A ca. 2.5-fold increase in the abundance of Smallmouth Bass abundance in assessment nets over the last seven years is a sign of improved recruitment to the fishery. Since the target population level of 4,500 to 6,000 cormorants has essentially been achieved, the eastern Lake Ontario cormorant program is expected to shift in 2007 from a population reduction focus towards a less intensive program intended to prevent population resurgence

    Mitigation of Double-crested Cormorant Impacts on Lake Ontario: From Planning and Practice to Product Delivery

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    The New York State Department of Environmental Conservation initiated a Double-crested Cormorant (Phalacrocorax auritus) control program in the eastern basin of Lake Ontario to mitigate cormorant impacts in 1999. Key objectives included improving the quality of Smallmouth Bass (Micropterus dolomieu) and other fisheries, restoring the structure and function of the warmwater fish community and reducing cormorant impacts to nesting habitats of other colonial waterbird species. In eight years of intensive control, cormorant numbers declined, with a corresponding reduction in estimated fish consumption. Diversity and numbers of co-occurring waterbirds either increased or have not been shown to be negatively impacted by management. Woody vegetation favorable to Black-crowned Night-Herons (Nycticorax nycticorax) has been maintained. A ca. 2.5-fold increase in the abundance of Smallmouth Bass abundance in assessment nets over the last seven years is a sign of improved recruitment to the fishery. Since the target population level of 4,500 to 6,000 cormorants has essentially been achieved, the eastern Lake Ontario cormorant program is expected to shift in 2007 from a population reduction focus towards a less intensive program intended to prevent population resurgence

    Data-driven management—a dynamic occupancy approach to enhanced rabies surveillance prioritization

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    Rabies lyssavirus (RABV) is enzootic in raccoons across the eastern United States. Intensive management of RABV by oral rabies vaccination (ORV) has prevented its spread westward and shown evidence of local elimination in raccoon populations of the northeastern US. The USDA, Wildlife Services, National Rabies Management Program (NRMP) collaborates with other agencies to implement broad-scale ORV and conducts extensive monitoring to measure the effectiveness of the management. Enhanced Rabies Surveillance (ERS) was initiated during 2005 and updated in 2016 to direct surveillance efforts toward higher-value specimens by assigning points to different methods of encountering specimens for collection (strange-acting, roadkill, surveillance-trapped, etc.; specimen point values ranged from 1 to 15). We used the 2016–2019 data to re-evaluate the point values using a dynamic occupancy model. Additionally, we used ERS data from 2012–2015 and 2016–2019 to examine the impact that the point system had on surveillance data. Implementation of a point system increased positivity rates among specimens by 64%, indicating a substantial increase in the efficiency of the ERS to detect wildlife rabies. Our re-evaluation found that most points accurately reflect the value of the surveillance specimens. The notable exception was that samples from animals found dead were considerably more valuable for rabies detection than originally considered (original points = 5, new points = 20). This work demonstrates how specimen prioritization strategies can be used to refine and improve ERS in support of wildlife rabies management
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