29 research outputs found

    PRELIMINARY EVALUATION OF A GRANULAR TRIMETHACARB FORMULATION FOR DETERRING GRAZING BY AMERICAN COOTS

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    In a 0.2 ha flight pen, groups of 4 American coots were tested to determine if their grazing activity could be affected by application of a registered granular-trimethacarb insecticide. In the 3 days following treatment (3 kg/ha, a.i.), grazing activity in the treated portions of the 200 m2 experimental plots was reduced an average of 47X. Overall use of the treated areas followed a similar pattern but was less consistent among groups. The addition of methylpyrazine, a strong odorant, produced a strong initial suppression of grazing activity in the treated halves of the plots. However, subsequent rain and a change in the coots\u27 grazing behavior prevented a definitive evaluation of the methylpyrazine treatment. Two birds that died during the trimethacarb-only portion of the study did not have abnormally low levels of brain cholinesterase. However, this finding does not preclude the possibility that they were unable to distinguish treated from untreated grass and consumed lethal amounts of trimethacarb. Additional investigation of methylpyrazine appears warranted; such materials may act to decrease the likelihood that birds will ingest lethal quantities of repellent

    Project Report No. 62, Site Index Equations for Loblolly and Slash Pine Plantations in East Texas, Update: Fall 1998

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    This update utilizes height-age pairs measured from 1982 - 1998. As a result, the number of observations available for analysis is 1,814 loblolly and 788 slash. It is anticipated that the equations in this Fall 1998 update may quantify the productivity of East Texas loblolly and slash pine plantations in a more accurate and reliable manner than the seven previous sets of equations

    Cellular Radiosensitivity: How much better do we understand it?

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    Purpose: Ionizing radiation exposure gives rise to a variety of lesions in DNA that result in genetic instability and potentially tumorigenesis or cell death. Radiation extends its effects on DNA by direct interaction or by radiolysis of H2O that generates free radicals or aqueous electrons capable of interacting with and causing indirect damage to DNA. While the various lesions arising in DNA after radiation exposure can contribute to the mutagenising effects of this agent, the potentially most damaging lesion is the DNA double strand break (DSB) that contributes to genome instability and/or cell death. Thus in many cases failure to recognise and/or repair this lesion determines the radiosensitivity status of the cell. DNA repair mechanisms including homologous recombination (HR) and non-homologous end-joining (NHEJ) have evolved to protect cells against DNA DSB. Mutations in proteins that constitute these repair pathways are characterised by radiosensitivity and genome instability. Defects in a number of these proteins also give rise to genetic disorders that feature not only genetic instability but also immunodeficiency, cancer predisposition, neurodegeneration and other pathologies. Conclusions: In the past fifty years our understanding of the cellular response to radiation damage has advanced enormously with insight being gained from a wide range of approaches extending from more basic early studies to the sophisticated approaches used today. In this review we discuss our current understanding of the impact of radiation on the cell and the organism gained from the array of past and present studies and attempt to provide an explanation for what it is that determines the response to radiation

    ASSESSMENT OF BIRD DAMAGE TO EARLY-RIPENING BLUEBERRIES IN FLORIDA

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    Bird damage to early-ripening Florida blueberries was estimated to be approximately 17% in 1988 (2 sites) and ranged from 17% to 75% in 1989 (3 sites) when a late winter freeze severely reduced expected yield. Monetary loss due to bird damage in 1989 may have exceeded $4500/ac at one site. In Florida, birds appear to have a significant impact on the early season fresh market blueberry industry. The problem is likely to worsen as the planting of high-value, early-ripening varieties spreads to other parts of the state and ripening times overlap with wintering frugivorous birds

    Sharp-shinned Hawk Feeds through a Chain Link Fence

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    Food Avoidance by Red-winged Blackbirds Conditioned with a Pyrazine Odor

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    FLIGHT PEN EVALUATION OF EYESPOT BALLOONS TO PROTECT CITRUS FROM BIRD DEPREDATIONS

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    The effectiveness of eyespot balloons in discouraging boat-tailed grackle (Ouiscalus major) use of a simulated orange grove was investigated in a series of 4-day trials. The mean distance to the trees of 6-bird experimental flocks was the same with a plain white balloon present as with no balloon. A white balloon with red and black eyespots kept birds at a greater distance from the trees throughout the trial. The presence of a black balloon with orange and yellow eyespots did not repel the birds from the grove. Observations of birds using the area within 1 m of the trees revealed no effect due to the eyespot balloons nor was the number of oranges pecked reduced in the presence of the eyespot balloons. These results were primarily due to a single bird that consistently ignored the white eyespot balloon during the 4-day trial, entered the grove, and avidly pecked the fruit. In combination with other crop protection devices, eyespot balloons may prove effective in deterring bird use of citrus trees
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