3,379 research outputs found

    Distribution, Abundance, and Feeding Habits of Juvenile Kingfish (Menticirrhus) Species Found in the North-Central Gulf of Mexico

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    Southern Kingfish (Menticirrhus americanus), Gulf Kingfish (Menticirrhus littoralis), and Northern Kingfish (Menticirrhus saxatilis) were collected by beam plankton trawl and seine along shoreline habitats in 2005 and 2006. Specific habitats included barrier island (surf zones and grass beds) and mainland (marsh edge and sandy shorelines) areas. Five hundred sixty-seven kingfish were collected during this study, with over 85% of the specimens collected in 2006. Densities of both M. americanus and M. littoralis peaked during summer, whereas densities of M. saxatilis peaked in spring. All three kingfish species co-occurred within surf zone and sandy shoreline habitats, but M. americanus was the dominant kingfish along protected sandy shorelines, and M. littoralis was the dominant kingfish along open surf zones. Several M. littoralis, which are known to be surf zone species, were also collected from mainland sandy shoreline. Only M. americanus was collected from marsh edges, and all three species were absent from grass beds. Stomachs of all three kingfish species at sizes \u3c 15 mm standard length (SL) most often contained calanoid copepods. Larger M. americanus (16–60 mm SL) fed most frequently on mysids, larger M. littoralis (31–60 mm SL) fed most frequently on bivalves, and larger M. saxatilis (31–60 mm SL) fed most frequently on both mysids and amphipods. The diversity of prey items increased with size for all three Menticirrhus species. This research provides a useful descriptive report on the distribution, abundance, and feeding habits of juvenile Menticirrhus species found in the north-central Gulf of Mexico

    FINDCHIRP: an algorithm for detection of gravitational waves from inspiraling compact binaries

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    Matched-filter searches for gravitational waves from coalescing compact binaries by the LIGO Scientific Collaboration use the FINDCHIRP algorithm: an implementation of the optimal filter with innovations to account for unknown signal parameters and to improve performance on detector data that has nonstationary and non-Gaussian artifacts. We provide details on the FINDCHIRP algorithm as used in the search for subsolar mass binaries, binary neutron stars, neutron star-black hole binaries, and binary black holes.Comment: 19 pages, 1 figure, journal version with Creative Commons 4.0 open-access license adde

    EC87-115 Breeding and Management Improve Quality of Switchgrass Pasture

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    Extension circular 87-115 is about breeding and management improves quality of switchgrass pasture

    EC00-153 Selecting Alfalfa Varieties for Nebraska

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    Yield potential, pest resistance and seed price should be considered when selecting alfalfa varieties in Nebraska. The most important variety decision on many farms and ranches is the selection of alfalfa. The choice of alfalfa variety affects production for three to 10 or more years, whereas varieties of annual crops can be change every year. This extension circular lists the alfalfa varieties that have been tested in Nebraska with commercial seed for two or more years since 1997 and marketed in the state. These are the 2000 results

    G77-357 Selecting Alfalfa Varieties for Nebraska (Revised December 1994)

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    The most important variety decision made on many farms and ranches is the selection of alfalfa varieties. The choice of alfalfa variety affects production for three to 10 or more years. Yield potential, pest resistance and seed price all should be considered in selecting alfalfa varieties in Nebraska. This NebGuide discusses them

    Synthesis of satellite (MODIS), aircraft (ICARTT), and surface (IMPROVE, EPA-AQS, AERONET) aerosol observations over eastern North America to improve MODIS aerosol retrievals and constrain surface aerosol concentrations and sources

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    We use an ensemble of satellite (MODIS), aircraft, and ground-based aerosol observations during the ICARTT field campaign over eastern North America in summer 2004 to (1) examine the consistency between different aerosol measurements, (2) evaluate a new retrieval of aerosol optical depths (AODs) and inferred surface aerosol concentrations (PM2.5) from the MODIS satellite instrument, and (3) apply this collective information to improve our understanding of aerosol sources. The GEOS-Chem global chemical transport model (CTM) provides a transfer platform between the different data sets, allowing us to evaluate the consistency between different aerosol parameters observed at different times and locations. We use an improved MODIS AOD retrieval based on locally derived visible surface reflectances and aerosol properties calculated from GEOS-Chem. Use of GEOS-Chem aerosol optical properties in the MODIS retrieval not only results in an improved AOD product but also allows quantitative evaluation of model aerosol mass from the comparison of simulated and observed AODs. The aircraft measurements show narrower aerosol size distributions than those usually assumed in models, and this has important implications for AOD retrievals. Our MODIS AOD retrieval compares well to the ground-based AERONET data (R = 0.84, slope = 1.02), significantly improving on the MODIS c005 operational product. Inference of surface PM2.5 from our MODIS AOD retrieval shows good correlation to the EPA-AQS data (R = 0.78) but a high regression slope (slope = 1.48). The high slope is seen in all AOD-inferred PM2.5 concentrations (AERONET: slope = 2.04; MODIS c005: slope = 1.51) and could reflect a clear-sky bias in the AOD observations. The ensemble of MODIS, aircraft, and surface data are consistent in pointing to a model overestimate of sulfate in the mid-Atlantic and an underestimate of organic and dust aerosol in the southeastern United States. The sulfate overestimate could reflect an excessive contribution from aqueous-phase production in clouds, while the organic carbon underestimate could possibly be resolved by a new secondary pathway involving dicarbonyls

    Time-Resolved Ultraviolet Observations of the Globular Cluster X-ray Source in NGC 6624: The Shortest Known Period Binary System

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    Using the Faint Object Spectrograph (FOS) aboard the Hubble Space Telescope, we have obtained the first time-resolved spectra of the King et al. ultraviolet-bright counterpart to the 11-minute binary X-ray source in the core of the globular cluster NGC 6624. This object cannot be readily observed in the visible, even from HST, due to a much brighter star superposed <0.1'' distant. Our FOS data show a highly statistically significant UV flux modulation with a period of 11.46+-0.04 min, very similar to the 685 sec period of the known X-ray modulation, definitively confirming the association between the King et al. UV counterpart and the intense X-ray source. The UV amplitude is very large compared with the observed X-ray oscillations: X-ray variations are generally reported as 2-3% peak-to-peak, whereas our data show an amplitude of about 16% in the 126-251 nm range. A model for the system by Arons & King predicts periodic UV fluctuations in this shortest-known period binary system, due to the cyclically changing aspect of the X-ray heated face of the secondary star (perhaps a very low mass helium degenerate). However, prior to our observations, this predicted modulation has not been detected. Employing the Arons & King formalism, which invokes a number of different physical assumptions, we infer a system orbital inclination 35deg<i<50 deg. Amongst the three best-studied UV/optical counterparts to the intense globular cluster X-ray sources, two are now thought to consist of exotic double-degenerate ultrashort period binary systems.Comment: 10 pages including 2 figures in Latex (AASTeX 4.0). Accepted for publication in vol. 482 (1997 June 10 issue) of The Astrophysical Journal (Letters

    Early Growth of Three Kingfish (Menticirrhus) Species Found in Coastal Waters of the Northern Gulf of Mexico

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    Southern kingfish (Menticirrhus americanus), gulf kingfish (M. littoralis), and northern kingfish (M. saxatilis) are members of the drum family (Sciaenidae) that are widespread in coastal habitats of the western Atlantic, including in the Gulf of Mexico (GOM). Despite their economic and ecological importance, little is known about growth of young kingfish. Young kingfish were collected from four different Mississippi shoreline habitats in 2005 and 2006; two associated with barrier islands and two along the mainland. Barrier island habitats included surf zones on the south shore and grass beds on the north shore. Mainland habitats were located along marsh-edges and sandy shorelines. Kingfish growth comparisons were made using analysis of covariance (ANCOVA) on 194 aged fish (127 M. americanus, 54 M. littoralis, and 13 M. saxatilis). Growth rates for all three species were generally similar ranging from about 0.7mm/day at 4-6 mm standard length (SL) to 1.9mm/day at 55-60mm SL. In 2005, M. americanus from marsh-edges grew significantly faster than those from sandy shorelines. Size-at-age of M. americanus and M. littoralis was significantly smaller in the spring than in the summer and fall, while both growth rate and size—at—age were similar in the summer and fall

    Investigating Perceptual Congruence Between Data and Display Dimensions in Sonification

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    The relationships between sounds and their perceived meaning and connotations are complex, making auditory perception an important factor to consider when designing sonification systems. Listeners often have a mental model of how a data variable should sound during sonification and this model is not considered in most data:sound mappings. This can lead to mappings that are difficult to use and can cause confusion. To investigate this issue, we conducted a magnitude estimation experiment to map how roughness, noise and pitch relate to the perceived magnitude of stress, error and danger. These parameters were chosen due to previous findings which suggest perceptual congruency between these auditory sensations and conceptual variables. Results from this experiment show that polarity and scaling preference are dependent on the data:sound mapping. This work provides polarity and scaling values that may be directly utilised by sonification designers to improve auditory displays in areas such as accessible and mobile computing, process-monitoring and biofeedback
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