2,671 research outputs found

    Sylvicola cinctus (Fabricius), the Hawaiian Wood Gnat, with Notes on the Family (Diptera: Anisopodidae)

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    The Hawaiian Wood Gnat is identified as Sylvicola cinctus (Fabricius). The family Anisopodidae is reviewed, and key to World genera is presented. Male and female genitalia of S. cinctus, S. fenestralis and Anisopus fuscatus (two other species likely to occur in Hawaii) are figured

    Austroascia Segersi, a new genus and species (Diptera: Syrphidae)

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    A taxonomic review of the Palpada ruficeps species group, with the description of a new flower fly from Colombia (Diptera: Syrphidae)

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    A new species of flower flies, Palpada prietorum Mengual spec. nov. (Diptera: Syrphidae: Eristalinae) is described from Cali, Colombia. The new species belongs to the ruficeps subgroup in the vinetorum species group. An identification key is provided for the species of the ruficeps subgroup, as well as a comparison of morphological diagnostic characters to separate these taxa. Fragments of the mitochondrial cytochrome c oxidase subunit I (COI) gene, the D2-3 region of the nuclear 28S rRNA gene and the nuclear internal transcribed spacer (ITS2) are supplied for two species, Palpada prietorum spec. nov. and Palpada ruficeps (Macquart, 1842)

    A conspectus of the flower fly genus Allograpta (Diptera: Syrphidae) with description of a new subgenus and species

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    A new subgenus [Allograpta (Costarica Mengual & Thompson), type Allograpta zumbadoi Thompson], and one new species [Allograpta (Costarica) nishida Mengual & Thompson; type-locality: Costa Rica, type-depository: Instituto Nacional de Biodiversidad de Costa Rica] of flower flies (Diptera: Syrphidae) are described from the Neotropical biotic region. A checklist of the world species of Allograpta including synonyms is provided, and a key to and diagnoses of the subgenera are also supplied. The phylogenetic relationships among Allograpta species, representing all hitherto detected morphological diversity of the genus, and related genera were studied under parsimony based on morphological characters

    Effects of Strong Magnetic Fields on Neutron Star Structure

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    We study static neutron stars with poloidal magnetic fields and a simple class of electric current distributions consistent with the requirement of stationarity. For this class of electric current distributions, we find that magnetic fields are too large for static configurations to exist when the magnetic force pushes a sufficient amount of mass off-center that the gravitational force points outward near the origin in the equatorial plane. (In our coordinates an outward gravitational force corresponds to lngtt/r>0\partial\ln g_{tt}/\partial r>0, where tt and rr are respectively time and radial coordinates and gttg_{tt} is coefficient of dt2dt^2 in the line element.) For the equations of state (EOSs) employed in previous work, we obtain configurations of higher mass than had been reported; we also present results with more recent EOSs. For all EOSs studied, we find that the maximum mass among these static configurations with magnetic fields is noticeably larger than the maximum mass attainable by uniform rotation, and that for fixed values of baryon number the maximum mass configurations are all characterized by an off-center density maximum.Comment: Submitted to the Astrophysical Journal. 37 pages, 8 figures, uses aastex macro

    Preliminary Validation of a Mobility Obstacle Course for Persons with Mobility Impairment

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    The purpose of this study was to assess the reliability and validity of a mobility obstacle course for women with mobility impairments. Participants included 72 adult women with permanent physical disabilities including arthritis, orthopedic conditions, paraplegia, and others. The 60-m course consisted of carpeted runways and turns, ramps, a doorway, a transfer, and object manipulation. Participants completed two trials, walking or wheeling through the course as quickly as possible, safely and without running. Total course time and peak heart rate data were correlated with SF-36 health survey subscales. Overall, peak heart rate was significantly (p \u3c .05) correlated with physical functioning (r = -.328), limitations due to physical functioning (r = .261), and pain (r = .296). Total course time was significantly correlated with physical functioning. These findings indicate very high reliability and preliminary evidence of validity

    Open-ocean submesoscale motions: a full seasonal cycle of mixed layer instabilities from gliders

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    The importance of submesoscale instabilities, particularly mixed-layer baroclinic instability and symmetric instability, on upper ocean mixing and energetics is well documented in regions of strong, persistent fronts such as the Kuroshio and the Gulf Stream. Less attention has been devoted to studying submesoscale flows in the open ocean, far from long-term mean geostrophic fronts, characteristic of a large proportion of the global ocean. We present a year-long, submesoscale-resolving time series of near-surface buoyancy gradients, potential vorticity and instability characteristics, collected by ocean gliders, that provides insight into open-ocean submesoscale dynamics over a full annual cycle. The gliders continuously sampled a 225 km2 region in the subtropical northeast Atlantic, measuring temperature, salinity and pressure along 292 short (\~{}20 km) hydrographic sections.Glider observations show a seasonal cycle in near-surface stratification. Throughout the fall (September through November), the mixed layer deepens, predominantly through gravitational instability, indicating that surface cooling dominates submesoscale restratification processes. During winter (December through March), mixed layer depths are more variable, and estimates of the balanced Richardson number, which measures the relative importance of lateral and vertical buoyancy gradients, depict conditions favorable to symmetric instability. The importance of mixed layer instabilities on the restratification of the mixed layer, as compared with surface heating and cooling, shows that submesoscale processes can reverse the sign of an equivalent heat flux up to 25{\%} of the time during winter. These results demonstrate that the open-ocean mixed layer hosts various forced and unforced instabilities, which become more prevalent during winter, and emphasize that accurate parameterizations of submesoscale processes are needed throughout the ocean

    The distance of M33 and the stellar population in its outskirts

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    We present deep V,I photometry of two $9.4' x 9.4' field in the outer regions of the M33 galaxy. We obtain a robust detection of the luminosity of the Red Giant Branch Tip (I{TRGB}=20.72 +- 0.08) from which we derived a new estimate of the distance modulus of M33, (m-M)_0=24.64 +- 0.15, corresponding to a distance D=847 +- 60 Kpc. By comparison of the color and magnitude of the observed Red Giant Branch stars with ridge lines of template globular clusters we obtained the photometric metallicity distribution of the considered fields in three different metallicity scales. The derived metallicity distributions are very similar over a range of distances from the galactic center 10' <= R <= 33', and are characterized by a well defined peak at [M/H] ~ -0.7 ([Fe/H] ~ -1.0, in the Zinn & West scale) and a weak metal-poor tail reaching [M/H] ~ -2.0. Our observations demonstrate that Red Giant Branch and Asymptotic Giant Branch stars have a radial distribution that is much more extended than the young MS stars associated with the star-forming disc.Comment: 10 pages,10 figures,accepted for publication in Astronomy & Astrophysic
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