1,794 research outputs found

    Non-Target Hazard Assessment of Using DRC-1339 Avicide to Manage Blackbirds in Sunflower

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    Terrestrial hazard assessments were conducted for the spring blackbird baiting program to protect sunflower crops. Risk Assessment methodology proposed by the Ecological Committee on FIFRA Risk Assessment Methods (ECOFRAM) and the method currently used by the U.S. Environmental Protection Agency (LD50s/ft2) were compared for their predictive strengths and for the ease of adapting the assessment to site specific conditions. While the ECOFRAM and LD50s/ft2 methods identified the same groups of organisms as being at risk, the flexibility of the ECOFRAM methodology allowed more latitude in adapting the assessment to unique behaviors of individual species. These risk assessment approaches indicate that blackbird baiting with DRC-1339 presents acute hazards to select nontarget birds like western meadowlarks and mourning doves but few hazards to most mammals or small granivorous birds like sparrows and finches. However, field experiments indicate that the mitigation measures currently employed in the baiting program, minimize the nontarget hazards

    A direct synthesis of racemic demethoxyaflatoxin B2

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    Aflatoxin analogue 19 was prepared by a direct sequence involving a novel silver-mediated cyclization to 12, the Michael addition of 16 with 17, and the oxidation of the Michael addition adduct. The overall yield of this six-step route is approximately 11%. The pathway is a flexible one that will permit the synthesis of analogues for toxicological analysis

    Observing Pulsars with a Phased Array Feed at the Parkes Telescope

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    During February 2016, CSIRO Astronomy and Space Science and the Max-Planck-Institute for Radio Astronomy installed, commissioned and carried out science observations with a phased array feed (PAF) receiver system on the 64m diameter Parkes radio telescope. Here we demonstrate that the PAF can be used for pulsar observations and we highlight some unique capabilities. We demonstrate that the pulse profiles obtained using the PAF can be calibrated and that multiple pulsars can be simultaneously observed. Significantly, we find that an intrinsic polarisation leakage of -31dB can be achieved with a PAF beam offset from the centre of the field of view. We discuss the possibilities for using a PAF for future pulsar observations and for searching for fast radio bursts with the Parkes and Effelsberg telescopes.Comment: 10 pages, 8 figures, 2 tables. It has been accepted for publication in PAS

    Prenatal Lead Exposure Risk Assessment by Vermont Maternity Care Providers

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    Introduction. One percent of women of childbearing age in the U.S. have blood lead levels ≥ 5 ug/dL, which are associated with maternal hypertension during pregnancy, neural tube and cardiac defects in infants, low birth weight, prematurity, and spontaneous abortion. It is unknown whether obstetrics providers in Vermont are screening their pregnant patients for lead levels and educating them on lead exposure risks. Objective. To gain an understanding of current lead screening practices in Vermont and issue recommendations for disseminating lead screening information. Methods. We developed and e-mailed a survey to practicing OB/GYN physicians, maternity care focused family medicine physicians, nurse midwives, and professional midwives. The survey assessed current screening practices for lead exposure in their pregnant patients, interest in receiving statewide guidelines, and guideline dissemination preferences. Results. Of the 41 respondents, 12% currently conduct risk assessments for lead exposure with all of their pregnant patients. Fifty four percent of maternity providers give all of their patients educational materials about lead exposure and risk of toxicity. Seventy one percent of maternity providers think that having guidelines provided by the Vermont Department of Health would encourage them to begin or continue lead exposure screening. The two preferred methods of communicating guidelines to physicians were grand rounds and email whereas non-physician providers preferred email and webinar. Discussion. The majority of pregnant patients in Vermont are not properly assessed or educated about lead risks. However, there is interest in having statewide standardized lead risk assessment guidelines, with dissemination preferences differing by provider type.https://scholarworks.uvm.edu/comphp_gallery/1248/thumbnail.jp

    On the reliability of polarization estimation using Rotation Measure Synthesis

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    We benchmark the reliability of the Rotation Measure (RM) synthesis algorithm using the 1005 Centaurus A field sources of Feain et al. (2009). The RM synthesis solutions are compared with estimates of the polarization parameters using traditional methods. This analysis provides verification of the reliability of RM synthesis estimates. We show that estimates of the polarization parameters can be made at lower S/N if the range of RMs is bounded, but reliable estimates of individual sources with unusual RMs require unconstrainted solutions and higher S/N. We derive from first principles the statistical properties of the polarization amplitude associated with RM synthesis in the presence of noise. The amplitude distribution depends explicitly on the amplitude of the underlying (intrinsic) polarization signal. Hence it is necessary to model the underlying polarization signal distribution in order to estimate the reliability and errors in polarization parameter estimates. We introduce a Bayesian method to derive the distribution of intrinsic amplitudes based on the distribution of measured amplitudes. The theoretically-derived distribution is compared with the empirical data to provide quantitative estimates of the probability that an RM synthesis solution is correct as a function of S/N. We provide quantitative estimates of the probability that any given RM synthesis solution is correct as a function of measured polarized amplitude and the intrinsic polarization amplitude compared to the noise.Comment: accepted for publication in the Astrophysical Journa

    Using Fatty Acid Profiles to Assess Dietary Intake of Sunflower in Red-Winged Blackbirds

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    In late summer, red-winged blackbirds forage heavily on ripening sunflower crops in the Dakotas. Sunflower achenes have a distinct fatty acid profile that should influence the fatty acid composition in tissues of these buds. To determine if fatty acid composition in tissue could be used as a biomarker indicating dietary history, we fed 18 red-winged blackbirds a sunflower diet for 2 weeks and compared fatty acid profiles in their muscle and liver tissues to a control group of red-winged blackbirds (n = 15) fed a birdseed mix supplemented with safflower seed. Three subjects from each treatment group were sacrificed at Day 0, 7, 14, and 21, with Day 0 the day the treated group was switched to sunflower. The remaining buds were sacrificed on Day 35. Breast muscle and liver tissue were collected, extracted, and analyzed for levels of linoleic, oleic, palmitic, and stearic acids. Differences existed in levels of all 4 fatty acids between treatment groups pooled across time (P ≤ 0.05, ANOVA). When comparing fatty acid profiles between treated and controls by day sacrificed, we observed differences in levels of ≥1 of the fatty acids at Day 7, 14, and 21 in breast muscle, and Day 7 and 14 in liver tissue (P ≤ 0.05, t-test).Within-bird comparisons of fatty acid levels in liver and breast indicated temporal lags in metabolism between tissue types (P ≤ 0.05, paired t-test). Our results demonstrated that fatty acids profiles in body tissues can be used as biomarkers to verify recent foraging in sunflower by red-winged blackbirds

    Blink patterns and lid-contact times in dry-eye and normal subjects

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    Purpose To classify blinks in dry eye and normal subjects into six subtypes, and to define the blink rate and duration within each type of blink, as well as the total lid-contact time/minute. Materials and methods This was a single-centered, prospective, double-blind study of eleven dry-eye and ten normal subjects. Predefined subjects watched a video while blinks were recorded for 10 minutes. Partial blinks were classified by percentage closure of maximal palpebral fissure opening: 25%, 50%, 75%. Complete blinks were characterized as full (>0 seconds), extended (>0.1 seconds), or superextended (>0.5 seconds). The mean duration of each type of blink was determined and standardized per minute as total lid-contact time. Results: Total blinks observed were 4,990 (1,414 normal, 3,756 dry eye): 1,809 (50.59%) partial and 1,767 (49.41%) complete blinks among dry-eye subjects versus 741 (52.90%) partial and 673 (47.60%) complete blinks among normal subjects. Only superextended blinks of ≥0.5-second duration were significantly more frequent in dry-eye subjects than normals (2.3% versus 0.2%, respectively; P=0.023). Total contact time was seven times higher in dry-eye subjects than normals (0.565 versus 0.080 seconds, respectively; P0.1 second), the average contact time (seconds) was four times longer in dry-eye versus normal subjects (2.459 in dry eye, 0.575 in normals; P=0.003). Isolating only superextended blinks (>0.5 seconds), average contact time was also significantly different (7.134 in dry eye, 1.589 in normals; P<0.001). The contact rate for all full closures was 6.4 times longer in dry-eye (0.045 versus 0.007, P<0.001) than normal subjects. Conclusion: Dry-eye subjects spent 4.5% of a minute with their eyes closed, while normal subjects spent 0.7% of a minute with their eyes closed. Contact time might play a role in the visual function decay associated with increased blink rates
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