2,596 research outputs found

    The Nesting Ecology of Woodpeckers in the Eastern Cascades and Their Interactions with Nest Competitors and Predators

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    Woodpeckers create nesting cavities for other birds and animals in forests. This creates dynamic interactions between both woodpeckers and these other animals. Using video cameras, we documented direct behavioral interactions between nesting woodpeckers and other animals in the Eastern Washington Cascades during the 2015 and 2016 breeding seasons. Additionally, we offered 937 students in a General Biology laboratory course to participate in this original research opportunity and described and the impact the experience had on the participants as well as the researchers. In 2015, Western Blubebirds took over two active Black-backed Woodpecker nests by physically attacking the woodpeckers. In 2016, almost half of the woodpecker nests were reused by other animals, with Western Bluebirds being are most common SCU. We found that some nests we reused within minutes to hours of vacancy. However, we were not able to significantly predict nest reuse or the presence of other animals at the nest. Parent woodpeckers towards avian cavity nesters when compared to rodent, predators, and other woodpeckers. Our fine-scale analysis provides a new window into behavioral interactions at woodpecker nests and same-season nest reuse, but it is limited by its scope. Thus, we suggest for larger-scale video studies examining behavioral interactions around the nest. About 15% of students in the course participated in our research, and we found that students accurately recorded data approximately 90% of the time. Most students came away from the experience with a more positive attitude towards undergraduate research and were able to restate the main research question. However, many students had difficulty understanding their role as a data collector. We suggest making the experience mandatory to include all students and placing a greater emphasis on the process of science

    Urban wind power and the private sector : community benefits, social acceptance and public engagement

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    Given the ambitious government targets for renewable energy generation in the UK, there has been a push by government and industry towards various types and scales of Renewable Energy Technologies (RETs). This paper explores the implications of commercial urban wind projects for local communities, drawing on a case study of proposals by ASDA to construct wind turbines in two semi-urban locations in the UK. The paper argues that community responses to the proposals were complex and varied and could not adequately be encapsulated by 'nimby' (not in my back yard) assignations. It concludes that while ASDA followed a process of consulting local people, this process highlighted the problems of the 'business as usual' approach to public engagement employed by ASDA, and assumptions made about public acceptance of RETs

    Contrast-Enhanced Ultrasound Imaging with Chirps: Signal Processing and Pulse Compression

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    Contrast-enhanced ultrasound imaging creates one of the worst case scenarios for pulse compression due to depth and frequency dependent attenuation, high level of harmonic generation, phase variations due to resonance behavior of microbubbles, and increased broadband noise by microbubble destruction. This study investigates the feasibility of pulse compression with a matched filter in the existence of microbubbles with resonant behavior. Simulations and experimental measurements showed that the scattered pressure from a microbubble population excited by a chirp waveform preserves its chirp rate even for harmonic frequencies. Although, pulse compression by a matched filter was possible due to the conservation of the chirp rate, an increase on sidelobe levels were observed at fundamental and second harmonic frequencies. Therefore, using chirp excitation and a matched filter pair will increase the contrast-to-tissue ratio with a trade-off of decreased image quality

    A phase velocity filter for the measurement of lamb wave dispersion

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    The complex, multi-modal and dispersive nature of guided waves makes them extremely effective in the non destructive evaluation of plate-like structures. Knowledge of the dispersion relation of a material is a prerequisite to many guided wave experiments. A frequency-phase velocity map is by far the most useful representation of dispersion. These phase velocity curves can be obtained numerically by solving the Lamb equations, however instabilities and unfamiliarity with the specimen's parameters makes experimentally obtained dispersion relation desirable. Transformations can be applied to an experimentally obtained frequency-wave number map but it requires prohibitively high number of sampling points in space to resolve modes across the full bandwidth of the transducer. The phase velocity filter described here is able to extract wavelets of a particular phase velocity irrespective of frequency. When applied to the acquisition of dispersion relation, the technique exhibits reduced artefacts and is able to extract modes across the full bandwidth of the excitation. Results show a bandwidth increase of approximately 58%

    Nitrogen requirements of borage and coriander

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    Non-Peer ReviewedCanola, borage and coriander were grown in a growth chamber with treatments of increasing rates of added nitrogen. Dry matter yield was measured at the early-flowering stage. Both borage and coriander had a lower potential dry matter yield and a corresponding lower nitrogen requirement than canola. Based on this experiment, borage and coriander fertilizer nitrogen could be recommended at about 30% less than the rates for canola. All of the crops responded strongly to added nitrogen up to their maximum yield potential. Measurements of leaf tissue nitrate, using an anion resin exchange membrane extraction, proved to be an accurate predictor of potential plant growth and a potential tool for fertilizer management

    Gaussian Belief with dynamic data and in dynamic network

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    In this paper we analyse Belief Propagation over a Gaussian model in a dynamic environment. Recently, this has been proposed as a method to average local measurement values by a distributed protocol ("Consensus Propagation", Moallemi & Van Roy, 2006), where the average is available for read-out at every single node. In the case that the underlying network is constant but the values to be averaged fluctuate ("dynamic data"), convergence and accuracy are determined by the spectral properties of an associated Ruelle-Perron-Frobenius operator. For Gaussian models on Erdos-Renyi graphs, numerical computation points to a spectral gap remaining in the large-size limit, implying exceptionally good scalability. In a model where the underlying network also fluctuates ("dynamic network"), averaging is more effective than in the dynamic data case. Altogether, this implies very good performance of these methods in very large systems, and opens a new field of statistical physics of large (and dynamic) information systems.Comment: 5 pages, 7 figure

    Spectrophotometric analysis of ternary uranyl systems to replace tri-N-butyl phosphate (TBP) in used fuel reprocessing

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    In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with UO2+2 are investigated in pH = 1 methanolic nitric acid media. These monoamides include N,N-dimethylacetamide (DMAA), N,N-diethylacetamide (DEAA), N,N-dibutylacetamide (DBAA) and N,N-dibutylbutanamide (DBBA). N,N,N′N′-tetraethylmalonamide (TEMA) and N,N,N′,N′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV–visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV–Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with UO2+2 in solution. The log10(K) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide–diamide–UO2 systems. Monoamide–diglycolamide–UO2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure
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