4,827 research outputs found

    Pion radiative weak decay from the instanton vacuum

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    We investigate the vector and axial-vector form factors for the pion radiative weak decays π+e+νeγ\pi^+\to e^+\nu_e \gamma and π+e+νee+e\pi^+\to e^+\nu_e e^+ e^-, based on the gauged effective chiral action from the instanton vacuum in the large NcN_c limit. The nonlocal contributions, which arise from the gauging of the action, enhance the vector form factor by about 20%20\,\%, whereas the axial-vector form factor is reduced by almost 30%30\,\%. Both the results for the vector and axial-vector form factors at the zero momentum transfer are in good agreement with the experimental data. The dependence of the form factors on the momentum transfer is also studied. The slope parameters are computed and compared with other works.Comment: 13 pages, 7 figures. Final version accepted for publication in Phys.Lett.

    Correction of Measurement Error in Monthly USDA Pig Crop: Generating Alternative Data Series

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    The imputed pig death loss contained in the reported monthly U.S. Department of Agriculture (USDA) pig crop data over the December 1995–June 2006 period ranged from 24.93% to 12.75%. Clearly, there are substantial measurement errors in the USDA monthly pig crop data. In this paper, we present alternative monthly U.S. pig crop data using the biological production process, which is compatible with prior knowledge of the U.S. hog industry. Alternative pig crop data are applied to a slaughter hog model and tested comparatively to USDA pig crop. Test results reject the validity of USDA pig crop data in favor of the alternative data.biological production process, measurement error, monthly USDA pig crop data, pig death loss, Agribusiness, Farm Management, Livestock Production/Industries, Q11, Q13, C12,

    The Effect of Fish Consumption on Blood Mercury Levels of Pregnant Women

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    In the present study, we examined the relationship between average fish consumption, as well as the type of fish consumed and levels of mercury in the blood of pregnant women. We also performed follow-up studies to determine if blood mercury levels were decreased after counseling and prenatal education. To examine these potential relationships, pregnant women were divided into two groups: a study group was educated to restrict fish intake, whereas a control group did not receive any prenatal education regarding fish consumption. We measured blood mercury level and performed follow-up studies during the third trimester to examine any differences between the two groups. Out of the 63 pregnant women who participated in our study, we performed follow-up studies with 19 pregnant women from the study group and 12 pregnant women from control group. The average initial blood mercury level of both groups was 2.94 µg/L, with a range of 0.14 to 10.75 µg/L. Blood mercury level in the group who ate fish more than four times per month was significantly higher than that of the group who did not consume fish (p = 0.02). In follow-up studies, blood mercury levels were decreased in the study group but slightly increased in the control group (p = 0.014). The maternal blood mercury level in late pregnancy was positively correlated with mercury levels of cord blood (r = 0.58, p = 0.047), which was almost twice the level found in maternal blood. Pregnant women who consume a large amount of fish may have high blood mercury levels. Further, cord blood mercury levels were much higher than that of maternal blood. Because the level of fish intake appears to influence blood mercury level, preconceptual education might be necessary in order decrease fish consumption
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