12,741 research outputs found

    The American species of the annulatipes group of the subgenus Lepidohelea, genus Forcipomyia (Diptera: Ceratopogonidae)

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    The annulatipes group of the genus Forcipomyia Meigen, subgenus Lepidohelea Kieffer, is represented in the Western Hemisphere by 12 species. Keys are presented for their identification, and to distinguish them from other groups of the subgenus Lepidohelea. The three previously known species, annulatipes Macfie, brasiliensis Macfie, and kuanoskeles Macfie, from southern Brazil, as well as the following nine new species, are described and illustrated: bahiensis, basifemoralis, bifida, convexipenis, euthystyla, gravesi, herediae, hobbsi, and weemsi

    Imputing historical statistics, soils information, and other land-use data to crop area

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    In foreign crop condition monitoring, satellite acquired imagery is routinely used. To facilitate interpretation of this imagery, it is advantageous to have estimates of the crop types and their extent for small area units, i.e., grid cells on a map represent, at 60 deg latitude, an area nominally 25 by 25 nautical miles in size. The feasibility of imputing historical crop statistics, soils information, and other ancillary data to crop area for a province in Argentina is studied

    Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach

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    Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither significantly inhibits groundwater use. Although both policies conserve similar amounts of groundwater, the regional cost of the tax policy to agriculture is more than the quota policy.integrated regional water policy model, Texas High Plains, water conservation policy, hydrology model, economic optimization model, Ogallala Aquifer, tax policy, quota policy, Agribusiness, Community/Rural/Urban Development, Food Security and Poverty, Land Economics/Use, Political Economy, Q30, Q31, Q38,

    Thermal and Non-thermal Plasmas in the Galaxy Cluster 3C 129

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    We describe new Chandra spectroscopy data of the cluster which harbors the prototypical "head tail" radio galaxy 3C 129 and the weaker radio galaxy 3C 129.1. We combined the Chandra data with Very Large Array (VLA) radio data taken at 0.33, 5, and 8 GHz (archival data) and 1.4 GHz (new data). We also obtained new HI observations at the Dominion Radio Astrophysical Observatory (DRAO) to measure the neutral Hydrogen column density in the direction of the cluster with arcminute angular resolution. The Chandra observation reveals extended X-ray emission from the radio galaxy 3C 129.1 with a total luminosity of 1.5E+41 erg/s. The X-ray excess is resolved into an extended central source of ~2 arcsec (1 kpc) diameter and several point sources with an individual luminosity up to 2.1E+40 erg/s. In the case of the radio galaxy 3C 129, the Chandra observation shows, in addition to core and jet X-ray emission reported in an earlier paper, some evidence for extended, diffuse X-ray emission from a region east of the radio core. The 12 arcsec x 36 arcsec (6 kpc x 17 kpc) region lies "in front" of the radio core, in the same direction into which the radio galaxy is moving. We use the radio and X-ray data to study in detail the pressure balance between the non-thermal radio plasma and the thermal Intra Cluster Medium (ICM) along the tail of 3C 129 which extends over 15 arcmin (427 kpc). Depending on the assumed lower energy cutoff of the electron energy spectrum, the minimum pressure of the radio plasma lies a factor of between 10 and 40 below the ICM pressure for a large part of the tail. We discuss several possibilities to explain the apparent pressure mismatch.Comment: Accepted for publication in MNRAS. Refereed manuscript. 14 pages, 8 figures, additional panel of Fig. 3 shows asymmetric ICM distributio

    Anaerobic Nitrogen Fixation in Some Iowa Soils

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    Data secured by various investigators have proven quite conclusively that the aerobic nitrogen-fixing bacteria of the genus Azotobacter are not active or even present in soils more acid than pH 6.0. Many of the soils in Iowa are more strongly acid than this, and while no Azotobacter have been found in them, some nitrogen fixation certainly occurs. It appears, therefore, that some other organisms or groups of organisms must be responsible

    The Neotropical Predaceous Midges of the genus \u3ci\u3eBezzia\u3c/i\u3e (Diptera: Ceratopogonidae) Part IV. The \u3ci\u3edentifemur\u3c/i\u3e and \u3ci\u3evenustula\u3c/i\u3e Groups

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    The dentifemur and venustula groups of the subgenus Homobezzia Macfie, genus Bezzia Kieffer, are represented in the Neotropical Region by 12 species. A key is presented for their identification, and to distinguish them from other groups of the subgenus Homobezzia. The two previously known species, B. venustula (Williston) and B. snowi Lane, are described and illustrated, as well as the following ten new species: aitkeni, bromeliae, cayoensis, dentifemur, filiductus, fusca, mexicana, nigritibialis, pseudovenustula, and raposoensis. Bezzia concoloripes Made is regarded as a junior synonym of B. venustula (Williston)

    Cupressus Bakeri-An Extension of the Known Botanical Range

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