839 research outputs found

    Use of satellite telemetry to delineate bald eagle activity centers for hazard mitigation and land planning within the upper Chesapeake Bay. Final Report

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    Sustaining the duel military and environmental stewardship missions on Aberdeen Proving Ground (APG) has become increasingly challenging as the number of eagles using the installation has grown dramatically. Military testing and training activities conducted on APG are vital to national security. APG likely holds the greatest conservation value for bald eagles of any federal property along the Atlantic Coast. The property supports a complex mixture of eagles including a growing breeding population that is rapidly approaching saturation, a large population of non‐breeding residents, and migrant populations from the northeast and southeast. Major activity centers such as active nests, communal roosts and foraging areas are protected under the disturb and sheltering provision of the federal Bald and Golden Eagle Protection Act. The level of site‐specific information on eagles required to tightly integrate their needs into the space requirements of a diverse and dynamic military operation has not been available. The focus of this project has been to collect and provide eagle information that will enable the incorporation of effective environmental planning into the military mission. Between 2007 and 2009 satellite transmitters were deployed on a large (n = 65) cohort of eagles that represent the cross section of populations that use APG. Between 2007 and 2011 transmitters collected nearly 700,000 GPS locations from within every state and Canadian province along the Atlantic Coast confirming APG’s role as a hub of eagle activity within eastern North America. Locations (n \u3e 320,000) within the upper Chesapeake Bay were used in spatial models to develop probability surfaces that identify high‐use activity centers by season within APG. Midnight locations (n \u3e 10,300) were used in separate spatial models to delineate communal roosts. Results of this study provide site‐specific information designed to inform future management decisions. Maps reveal the locations of significant communal roosts, foraging areas, loafing areas and movement corridors used by eagles on APG. Levels of use are quantified by location to facilitate prioritization of sites for management consideration. Seasonal and time‐of‐day patterns are provided to inform the scheduling of activities. The intersection of activity centers with the electrical infrastructure is examined to identify locations with the highest mortality risk. Lines intersecting with high‐use activity centers have produced mortality rates that are 42 times higher than lines intersecting with low‐use areas. Site‐specific information is provided to allow for the phasing of hazard mitigation. This report concludes the largest investigation of space use by bald eagles ever conducted. The project has clarified several aspects of eagle ecology within the upper Chesapeake Bay and has moved the science of eagle management forward in a way that will inform management throughout the species range. The still ongoing tracking database holds a great deal of promise for new ecological discoveries and management solutions

    Seasonal Variation in Space Use by Nonbreeding Bald Eagles Within the Upper Chesapeake Bay

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    Access to food resources is essential to self-maintenance and reproduction and, for species of conservation concern, foraging areas are considered critical habitat. Human disturbance is an important factor restricting access to prey resources for Bald Eagles (Haliaeetus leucocephalus) and guidelines in the Chesapeake Bay have been developed to mitigate its impact. However, our ability to implement such guidelines has been limited by a lack of information on important foraging areas. We used Brownian bridge movement modeling to develop a population-wide utilization probability surface for Bald Eagles along shorelines within the upper Chesapeake Bay. We used locations (n  =  320 304) for individuals (n  =  63) tracked with GPS satellite transmitters between 2007 and 2011 in the analysis. We examined seasonal variation by developing utilization surfaces for summer and winter. Although shoreline use was widespread, segments receiving high levels of activity were relatively rare. Shoreline classified as having the highest category of use and accounting for 10% of the total utilization made up 0.41% and 0.55% of the total shoreline for winter and summer, respectively. From a management perspective, there is a clear pattern of diminishing returns in conservation value for including sequentially lower-use shorelines in land-use management plans. Shoreline use shifted dramatically in both location and extent between seasons. During the summer months, use was highly concentrated on shorelines along the main stem of the Chesapeake Bay or along major (\u3e1 km wide) tributaries. During the winter months, use shifted away from the main stem of the bay and was more focused on minor (wide) tributaries and inland ponds. Seasonal shifts in shoreline use suggest the need for season-based management objectives

    Using an Approach-Avoidance Framework to Understand the Relationship between Non-Lethal Weapons and Performance

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    It is proposed that performance degradation from exposure to non-lethal technology is mediated by impulsive and reflective approachavoidance motivation. An approach-avoidance motivational framework was used to specify a four-stage information processing model that predicts performance degradation. The first stage is Evaluation: it processes physiological, sensory, perceptual, and cognitive information. The second stage is Comparison: it processes the content of the Evaluation into avoidance and approach motivational indices. The third stage is Probability: it processes information from previous stages into a probability of choosing to continue or abandon goal-directed behavior. Finally, the fourth stage is Performance: it processes performance accuracy on a given task and occurs only when people continue their goal after dissuasive technology exposure. Depending on previous stages, performance can be degraded on tasks relevant to goal completion. An experiment was used to validate the model. Results supported the hypothesis that information is processed using the approach-avoidance motivational framework

    Optimizing a buck voltage regulator and the number of decoupling capacitors for a PDN application

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    An optimization methodology to determine the best values of the compensation elements of a buck voltage regulator (VR) as well as the optimal number of decoupling capacitors in a power delivery network (PDN) application is proposed. A state average equivalent circuit model of the buck converter is employed. The proposed optimization methodology gradually finds the best compensation parameter values of a buck converter VR to meet some stability criteria in a PDN application. Additionally, the number of parallel decoupling capacitors in the PDN is minimized to simultaneously meet a frequency-domain impedance profile specification and a time-domain voltage droop requirement.ITESO, A.C

    FALCONTRAK: Final Report

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    FalconTrak is a cooperative project designed to answer questions about the movements and survival of Peregrine Falcons (Falco peregrinus) within the mid-Atlantic region. We tracked 61 falcons between 2001 and 2011 with solar-powered, satellite transmitters to investigate the spatial dynamics of their annual cycle and to identify causes of mortality. Birds included 40 females and 21 males from coastal bridges (20), nesting towers (36), a high-rise building (2), and a captive breeder (3). Birds were either released from mountain hack sites (31) or allowed to fledge in situ (30). We received 66,343 signals of usable quality from transmitters. Movement patterns were used to subdivide the annual cycle into biologically meaningful units. Periods used included 1) Pre-dispersal, 2) post-dispersal, 3) fall migration, 4) winter, 5) spring migration, and 6) summer. More than half of the falcons that survived into the fall period migrated south of the mid-Atlantic region. Individuals did not change their migratory status between years. On average, southbound migration lasted 23 days and birds traveled 3,106 km. Fledging location had a dramatic influence on both migratory route and the location of winter home ranges. Birds that were fledged on the coast were the only birds to migrate to the tropics. Two of these birds crossed over to the Pacific Coast and wintered in Panama and Columbia. Birds from Shenandoah National Park and Harpers Ferry remained in the mid-Atlantic or migrated relatively short distances to the southern Piedmont. Birds fledged from the New River Gorge were the only birds to migrate down the Appalachians and winter along the Gulf Coast. Birds that did not migrate settled within winter home ranges 1.5 months earlier than those that migrated. Birds established winter home ranges over a wide geographic area ranging from western Long Island, NY to Buenaventura, Columbia (3 to 41° N. latitude). All of the non-migratory birds moved north and east of their fledging sites, most wintering near water in the northern mid-Atlantic Coastal Plain. Some of these birds established permanent home ranges. Most of the migratory birds moved to southern latitudes and established home ranges near major coastlines. Winter home ranges (50% kernel) varied widely between individuals ranging from 101 to 2,362 square kilometers . Spring migration was more rapid and direct compared to fall migration averaging only 15 days. Arrival within the summer home range was in May following the first spring migration and in March following the second. Summer home ranges were confined to the mid-Atlantic region and were distributed from Virginia to upstate New York. Five individuals were tracked to breeding territories along the eastern shore of Virginia, near Charles Town, WV, near Baltimore, MD, and on Long Island, NY. Cause of death was assigned to 24 falcons. Of these 11 were believed to be predated, 7 flew into man-made structures, 3 were killed in storms, 1 was hit by a truck, 1 drowned, and 1 was lost at sea. Predators believed to account for the most mortality included Great Horned Owls and adult Peregrine Falcons. Birds flew into transmission lines, towers, a high-rise building, and the side of a barn. The bird lost at sea was flying out over the open ocean and was lost near Bermuda

    Power Delivery Network Impedance Profile and Voltage Droop Optimization

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    The design process of power delivery networks (PDN) in modern computer platforms is becoming more relevant and complex due to its relationship with high-frequency effects on signal integrity. When circuits start operating, the changing current flowing through the PDN produces fluctuations creating voltage noise. Unsuccessful noise control can compromise data integrity. A suitable PDN design approach is the use of decoupling capacitors to lower the impedance profile and mitigate current surges, ensuring a small variation in the power supply voltage under significant transient current loads. An optimization approach to determine the number of decoupling capacitors in a PDN is presented in this paper, aiming at decreasing the amount of decoupling capacitors without violating the PDN design specifications, looking at both the impedance profile in the frequency domain and the resulting voltage droop in the transient time-domain.ITESO, A.C
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