797 research outputs found

    Record of Anthophora (Clisodon) terminalis in a wooden trap-nesting block and comparison to available nesting information (Hymenoptera: Apidae)

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    Bee nesting substrate choice can influence habitat use, conservation effort efficacy, and population or landscape-use modeling, but information on nesting sites are often scattered in the literature. Here we bring together the available information on nests of a widespread bee, Anthophora (Clisodon) terminalis Cresson, and describe an unusual new nesting substrate use for this species

    Megachile (Megachile) montivaga (Hymenoptera: Megachilidae) nesting in live thistle (Asteraceae: Cirsium)

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    Although Megachile Latreille (leafcutter bees) are well known for their diverse nesting habits, records of the genus nesting in live plants are rare.  Here, we report the widespread Megachile (Megachile) montivaga Cresson nesting in live thistle (Cirsium neomexicanum Gray), the first explicit record of this behavior in the Nearctic

    Paper Session I-A - Unmanned Aerial Vehicles as Technology Demonstrators for Advanced Range Systems

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    This project consists of the development and operation of an unmanned aerial vehicle (UAV) as a technology demonstration test bed for advanced range systems under development at Kennedy Space Center. The goal is to acquire a reliable, rapidly accessible vehicle for initial flight testing of electronic payloads through a limited portion of airspace to verify basic communications, command and control, tracking, and telemetry functions. The cost and schedule benefits of the project should exceed the other available options of flight in actual manned aircraft or sounding rockets. The vehicle will be remotely piloted with a reliable command and control system independent of the devices under test. It must account for any failure modes, and have contingencies to maximize safety of the operations. The UAV will provide standardized mounting, protection, and power to the devices under test. Considerations of airspace, FAA regulations, and authorizations for UAV operations must be thoroughly evaluated. This rapid demonstration capability will expedite development and initial. testing of advanced range systems projects, and provide gains in overall UAV knowledge, at a reasonable cost. The project fits well within existing ARTWG (Advanced Range Technology Working Group) Roadmaps for the future of Range Systems

    Assessing the Accuracy of Complex Refractive Index Retrievals from Single Aerosol Particle Cavity Ring-Down Spectroscopy

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    <p>Cavity ring-down spectroscopy (CRDS) of single, optically manipulated aerosol particles affords quantitative retrieval of refractive indices for particles of fixed or evolving composition with high precision. Here, we quantify the accuracy with which refractive index determinations can be made by CRDS for single particles confined within the core of a Bessel laser beam and how that accuracy is degraded as the particle size is progressively reduced from the coarse mode (>1 μm radius) to the accumulation mode (<500 nm radius) regime. We apply generalized Lorenz–Mie theory to the intra-cavity standing wave to explore the effect of particle absorption on the distribution of extinction cross section determinations resulting from stochastic particle motion in the Bessel beam trap. The analysis provides an assessment of the accuracy with which the real, <i>n</i>, and imaginary, κ, components of the refractive index can be determined for a single aerosol particle.</p> <p>Published with license by American Association for Aerosol Research</p> <p><a href="https://www.tandfonline.com/pb-assets/tandf/Migrated/UAST_VideoAbstract_Transcript.pdf" target="_blank">Read the transcript</a></p> <p><a href="https://vimeo.com/263371383" target="_blank">Watch the video on Vimeo</a></p

    A comparison of two statistical postprocessing methods for heavy-precipitation forecasts over India during the summer monsoon

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    Accurate ensemble forecasts of heavy precipitation in India are vital for many applications and essential for early warning of damaging flood events, especially during the monsoon season. In this study we investigate to what extent Quantile Mapping (QM) and Ensemble Model Output Statistics (EMOS) statistical postprocessing reduce errors in precipitation ensemble forecasts over India, in particular for heavy precipitation. Both methods are applied to day-1 forecasts at 12-km resolution from the 23-member National Centre for Medium Range Weather Forecasting (NCMRWF) global ensemble prediction system (NEPS-G). By construction, QM leads to distributions close to the observed ones, while EMOS optimizes the ensemble spread, and it is not a priori clear which is better suited for practical applications. The methods are therefore compared with respect to several key aspects of the forecasts: local distributions, ensemble spread, and skill for forecasting precipitation amounts and the exceedance of heavy-precipitation thresholds. The evaluation includes rank histograms, Continuous Ranked Probability Skill Scores (CRPSS), Brier Skill Scores (BSS), reliability diagrams, and receiver operating characteristic. EMOS performs best not only with respect to correcting under- or overdispersive ensembles, but also in terms of forecast skill for precipitation amounts and heavy precipitation events, with positive CRPSS and BSS in most regions (both up to about 0.4 in some areas), while QM in many regions performs worse than the raw forecast. QM performs best with respect to the overall local precipitation distributions. Which aspects of the forecasts are most relevant depends to some extent on how the forecasts are used. If the main criteria are the correction of under- or overdispersion, forecast reliability, match between the forecasted distribution for individual days and observations (CRPSS), and the skill in forecasting heavy-precipitation events (BSS), then EMOS is the better choice for postprocessing NEPS-G forecasts for short lead times
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