135 research outputs found

    Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1997

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    Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southern pea, watermelon, cantaloupe, tomato, blackberry, and grape. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides

    Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1998

    Get PDF
    Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southernpeas, watermelon, cantaloupe, summer squash, and grapes. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides

    Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1999

    Get PDF
    Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Because of the smaller acreage of these crops compared with major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach and other greens, southernpeas, tomatoes, and grapes

    Young stars at large distances from the galactic plane: mechanisms of formation

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    We have collected from the literature a list of early-type stars, situated at large distances from the galactic plane, for which evidence of youth seems convincing. We discuss two possible formation mechanisms for these stars: ejection from the plane by dynamical interactions within small clusters, and formation away from the plane, via induced shocks created by spiral density waves. We identify the stars that could be explained by each mechanism. We conclude that the ejection mechanism can account for about two thirds of the stars, while a combination of star formation at z = 500-800 pc from the plane and ejection, can account for 90 percent of these stars. Neither mechanism, nor both together, can explain the most extreme examples.Comment: 6 pages, No figures. Sixth Pacific Rim Conference on Stellar Astrophysics - A tribute to Helmut Abt, (Kluwer

    SkyMapper Southern Survey: First Data Release (DR1)

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    We present the first data release (DR1) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia. Here, we present the survey strategy, data processing, catalogue construction and database schema. The DR1 dataset includes over 66,000 images from the Shallow Survey component, covering an area of 17,200 deg2^2 in all six SkyMapper passbands uvgrizuvgriz, while the full area covered by any passband exceeds 20,000 deg2^2. The catalogues contain over 285 million unique astrophysical objects, complete to roughly 18 mag in all bands. We compare our grizgriz point-source photometry with PanSTARRS1 DR1 and note an RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on the order of 1%. Astrometric precision is better than 0.2 arcsec based on comparison with Gaia DR1. We describe the end-user database, through which data are presented to the world community, and provide some illustrative science queries.Comment: 31 pages, 19 figures, 10 tables, PASA, accepte

    SkyMapper Southern Survey: Second Data Release (DR2)

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    We present the second data release (DR2) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia, using six optical filters: u,v,g,r,i,zu,v,g,r,i,z. DR2 is the first release to go beyond the ∌\sim18mag (10σ{\sigma}) limit of the Shallow Survey released in DR1, and includes portions of the sky at full survey depth that reach >21mag in gg and rr filters. The DR2 photometry has a precision as measured by internal reproducibility of 1% in uu and vv, and 0.7% in grizgriz. More than 21 000 deg2^2 have data in some filters (at either Shallow or Main Survey depth) and over 7 000 deg2^2 have deep Main Survey coverage in all six filters. Finally, about 18 000 deg2^2 have Main Survey data in ii and zz filters, albeit not yet at full depth. The release contains over 120 000 images, as well as catalogues with over 500 million unique astrophysical objects and nearly 5 billion individual detections. It also contains cross-matches with a range of external catalogues such as Gaia DR2, Pan-STARRS1 DR1, GALEX GUVcat, 2MASS, and AllWISE, as well as spectroscopic surveys such as 2MRS, GALAH, 6dFGS, and 2dFLenS.Comment: 21 pages, 17 figures. As of 25 Aug 2020, DR2 is available to the world at http://skymapper.anu.edu.a

    Nova Sagittarii 1998 (V4633 Sgr) - a permanent superhump system or an asynchronous polar?

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    We report the results of observations of V4633 Sgr (Nova Sagittarii 1998) during 1998-2000. Two photometric periodicities were present in the light curve during the three years of observations: a stable one at P=3.014 h, which is probably the orbital period of the underlying binary system, and a second one of lower coherence, approximately 2.5 per cent longer than the former. The latter periodicity may be a permanent superhump, or alternatively, the spin period of the white dwarf in a nearly synchronous magnetic system. A third period, at P=5.06 d, corresponding to the beat between the two periods was probably present in 1999. Our results suggest that a process of mass transfer took place in the binary system since no later than two and a half months after the nova eruption. We derive an interstellar reddening of E(B-V)~0.21 from our spectroscopic measurements and published photometric data, and estimate a distance of d~9 kpc to this nova.Comment: 13 pages, latex, 7 figures, accepted for publication in MNRA

    One-Loop Corrections to Two-Quark Three-Gluon Amplitudes

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    We present the one-loop QCD amplitudes for two external massless quarks and three external gluons (qˉqggg\bar{q}qggg). This completes the set of one-loop amplitudes needed for the next-to-leading-order corrections to three-jet production at hadron colliders. We also discuss how to use group theory and supersymmetry to minimize the amount of calculation required for the more general case of one-loop two-quark nn-gluon amplitudes. We use collinear limits to provide a stringent check on the amplitudes.Comment: plain Tex, 46 pages with 13 figures in a uuencoded file, corrected case j=1 of eq. (IV.7), and signs in eq. (4.9
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