572 research outputs found

    The Ability of Specific-wavelength LED Lights to Attract Night-flying Insects

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    This paper describes a portable collecting light, designed by the authors, that weighs 0.3 kg, is powered by 8 AA batteries, and uses 9 light-emitting diodes (LEDs) to attract night-flying insects. Five different wavelengths of these LED lights, all within the long-wave ultraviolet spectrum, were compared to each other and to a commercially-available 15w fluorescent ultraviolet tube light for their abilities to collect insects over a series of 5 nights in July 2016. There was no difference in order richness, total specimen abundance, or the specimen abundance of most common orders between any of the wavelengths tested. Most LED wavelengths, however, caught fewer Diptera specimens than the fluorescent tube light, largely due to a lower abundance of chironomid midges. Differences in specimen abundance were greater based on sampling date or specific sampling location than based on type of collecting light. Due to their greater portability and possibly lower bycatch of Diptera, these new LED lights are presented as a potential alternative to ultraviolet tube lights

    The Ability of Specific-wavelength LED Lights to Attract Night-flying Insects

    Get PDF
    This paper describes a portable collecting light, designed by the authors, that weighs 0.3 kg, is powered by 8 AA batteries, and uses 9 light-emitting diodes (LEDs) to attract night-flying insects. Five different wavelengths of these LED lights, all within the long-wave ultraviolet spectrum, were compared to each other and to a commercially-available 15w fluorescent ultraviolet tube light for their abilities to collect insects over a series of 5 nights in July 2016. There was no difference in order richness, total specimen abundance, or the specimen abundance of most common orders between any of the wavelengths tested. Most LED wavelengths, however, caught fewer Diptera specimens than the fluorescent tube light, largely due to a lower abundance of chironomid midges. Differences in specimen abundance were greater based on sampling date or specific sampling location than based on type of collecting light. Due to their greater portability and possibly lower bycatch of Diptera, these new LED lights are presented as a potential alternative to ultraviolet tube lights

    Local analogues of high-redshift star-forming galaxies: integral field spectroscopy of green peas

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We use integral field spectroscopy, from the SWIFT and Palm3K instruments, to perform a spatially-resolved spectroscopic analysis of four nearby highly star-forming `green pea' (GP) galaxies, that are likely analogues of star-forming systems at z~2.5-3. By studying emission-line maps in Hα\alpha, [NII]λλ\lambda \lambda6548,6584 and [SII]λ\lambdaλ\lambda6716,6731, we explore the kinematic morphology of these systems and constrain properties such as gas-phase metallicities, electron densities and gas-ionization mechanisms. Two of our GPs are rotationally-supported while the others are dispersion-dominated systems. The rotationally-supported galaxies both show evidence for recent or ongoing mergers. However, given that these systems have intact disks, these interactions are likely to have low mass ratios (i.e. minor mergers), suggesting that the minor-merger process may be partly responsible for the high SFRs seen in these GPs. Nevertheless, the fact that the other two GPs appear morphologically undisturbed suggests that mergers (including minor mergers) are not necessary for driving the high star formation rates in such galaxies. We show that the GPs are metal-poor systems (25-40 per cent of solar) and that the gas ionization is not driven by AGN in any of our systems, indicating that AGN activity is not co-eval with star formation in these starbursting galaxies.Peer reviewedFinal Published versio

    Seasonal Changes of Benthic Macroinvertebrate Functional Feeding Group Biomass Within Forest and Meadow Habitats of a First-order Michigan (USA) Stream

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    Little is known about seasonal changes in stream benthic macroinvertebrate assemblages. We determined the ash-free dry mass of macroinvertebrates within a forested and a meadow reach of Fairbanks Creek in northern Lower Michigan throughout all seasons of 2018 and 2019. The macroinvertebrate assemblage of the forested reach was dominated by invertebrates in the shredder functional feeding group (FFG), whereas the meadow reach was composed primarily of scrapers and filtering collectors. Regardless of reach, the biomass of all FFGs was low during the winter and early spring, peaked in May or June, and gradually declined throughout the summer and fall. General trends in biomass were the same for both years of the study, although 2018 had overall higher biomass despite being a slightly cooler year

    Distribution of slow and fast rotators in the Fornax cluster

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    We present integral field spectroscopy of 10 early-type galaxies in the nearby, low-mass, Fornax cluster, from which we derive spatially resolved stellar kinematics. Based on the morphologies of their stellar velocity maps we classify 2/10 galaxies as slow rotators, with the remaining eight galaxies fast rotators. Supplementing our integral field observations with morphological and kinematic data from the literature, we analyse the ‘kinematic’ type of all 30 galaxies in the Fornax cluster brighter than MK = −21.5 mag (M* ∼ 6 × 109 M⊙). Our sample's slow rotator fraction within one virial radius is 7+4−6 per cent. 13+8−6 per cent of the early-type galaxies are slow rotators, consistent with the observed fraction in other galaxy aggregates. The fraction of slow rotators in Fornax varies with cluster-centric radius, rising to 16+11−8 per cent of all kinematic types within the central 0.2 virial radii, from 0 per cent in the cluster outskirts. We find that, even in mass-matched samples of slow and fast rotators, slow rotators are found preferentially at higher projected environmental density than fast rotators. This demonstrates that dynamical friction alone cannot be responsible for the differing distributions of slow and fast rotators. For dynamical friction to play a significant role, slow rotators must reside in higher mass sub-haloes than fast rotators and/or form in the centres of groups before being accreted on to the cluster

    On the distribution of galaxy ellipticity in clusters

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    We study the distribution of projected ellipticity n(ϵ) for galaxies in a sample of 20 rich (Richness ≥ 2) nearby (z 0.4), therefore it is not a consequence of the increasing fraction of round slow rotator galaxies near cluster centers. Furthermore, the ϵ-R relation persists for just smooth flattened galaxies and for galaxies with de Vaucouleurs-like light profiles, suggesting that the variation of the spiral fraction with radius is not the underlying cause of the trend. We interpret our findings in light of the classification of early type galaxies (ETGs) as fast and slow rotators. We conclude that the observed trend of decreasing ϵ towards the centres of clusters is evidence for physical effects in clusters causing fast rotator ETGs to have a lower average intrinsic ellipticity near the centres of rich clusters

    On the distribution of galaxy ellipticity in clusters

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    open4We study the distribution of projected ellipticity n(ε) for galaxies in a sample of 20 rich (Richness ≥ 2) nearby (z 0.4), therefore it is not a consequence of the increasing fraction of round slow rotator galaxies near cluster centers. Furthermore, the ε-R relation persists for just smooth flattened galaxies and for galaxies with deVaucouleurs-like light profiles, suggesting that the variation of the spiral fractionwith radius is not the underlying cause of the trend. We interpret our findings in light of the classification of early type galaxies (ETGs) as fast and slow rotators. We conclude that the observed trend of decreasing ε towards the centres of clusters is evidence for physical effects in clusters causing fast rotator ETGs to have a lower average intrinsic ellipticity near the centres of rich clusters.openD'Eugenio F.; Houghton R.C.W.; Davies R.L.; Dalla Bonta' E.D'Eugenio, F.; Houghton, R. C. W.; Davies, R. L.; Dalla Bonta', E

    Seasonal characteristics of bottom boundary layer detachment at the shelfbreak front in the Middle Atlantic Bight

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    Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C03049, doi:10.1029/2003JC002032.The seasonality of various characteristics of the detached bottom boundary layer of the Middle Atlantic Bight shelfbreak front is examined using a collection of high-resolution transects across the front. The analysis follows previous methodology in which accumulated temperature change along isopycnals within the front is used to infer the location of the detached layer. The seasonal mean isopycnal at which detachment occurs (approximately 26.0 kg m−3) is fairly constant throughout the year. However, the vertical scale of the detached layer varies significantly with season, extending 60−80 m above the bottom in winter and spring, but only 20−40 m above the bottom in summer. The vertical scale is controlled by the strength and depth of the seasonal pycnocline. The observations suggest that the detached layer is capable of extending into the euphotic zone during winter and spring.This work was funded by the Office of Naval Research under contracts N00014-01-1-0931 (C. L. and G. G.) and N00014-01-1-0772 (C. L. and G. G.) and by the National Science Foundation under grant OCE-0095261 (R. P.

    Climatological mean circulation at the New England shelf break

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    Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 41 (2011): 1874–1893, doi:10.1175/2011JPO4604.1.A two-dimensional cross-shelf model of the New England continental shelf and slope is used to investigate the mean cross-shelf and vertical circulation at the shelf break and their seasonal variation. The model temperature and salinity fields are nudged toward climatology. Annual and seasonal mean wind stresses are applied on the surface in separate equilibrium simulations. The along-shelf pressure gradient force associated with the along-shelf sea level tilt is tuned to match the modeled and observed depth-averaged along-shelf velocity. Steady-state model solutions show strong seasonal variation in along-shelf and cross-shelf velocity, with the strongest along-shelf jet and interior onshore flow in winter, consistent with observations. Along-shelf sea level tilt associated with the tuned along-shelf pressure gradient increases shoreward because of decreasing water depth. The along-shelf sea level tilt varies seasonally with the wind and is the strongest in winter and weakest in summer. A persistent upwelling is generated at the shelf break with a maximum strength of 2 m day−1 at 50-m depth in winter. The modeled shelfbreak upwelling differs from the traditional view in that most of the upwelled water is from the upper continental slope instead of from the shelf in the form of a detached bottom boundary layer.WGZ was supported by the Woods Hole Oceanographic Institution postdoctoral scholarship program. GGGandDJMwere supported byONRGrant N-00014- 06-1-0739
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