488 research outputs found

    Dominant g(9/2)^2 neutron configuration in the 4+1 state of 68Zn based on new g factor measurements

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    The gg factor of the 41+4_1^+ state in 68^{68}Zn has been remeasured with improved energy resolution of the detectors used. The value obtained is consistent with the previous result of a negative gg factor thus confirming the dominant 0g9/20g_{9/2} neutron nature of the 41+4_1^+ state. In addition, the accuracy of the gg factors of the 21+2_1^+, 22+2_2^+ and 31−3_1^- states has been improved an d their lifetimes were well reproduced. New large-scale shell model calculations based on a 56^{56}Ni core and an 0f5/21pg9/20f_{5/2}1pg_{9/2} model space yield a theoretical value, g(41+)=+0.008g(4_1^+) = +0.008. Although the calculated value is small, it cannot fully explain the experimental value, g(41+)=−0.37(17)g(4_1^+) = -0.37(17). The magnitude of the deduced B(E2) of the 41+4_1^+ and 21+2_1^+ transition is, however, rather well described. These results demonstrate again the importance of gg factor measurements for nuclear structure determination s due to their specific sensitivity to detailed proton and neutron components in the nuclear wave functions.Comment: 7 pages, 3 figs, submitted to PL

    First measurement and shell model interpretation of the g factor of the 21+ state in self-conjugate radioactive 44Ti

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    AbstractThe g factor of the 21+ state in radioactive 44Ti has been measured for the first time with the technique of α transfer to 40Ca beams in inverse kinematics in combination with transient magnetic fields, yielding the value, g(21+)=+0.52(15). In addition, the lifetimes of the 21+, τ=3.97(28) ps, and the 41+ states, τ=0.65(6) ps, were redetermined with higher precision using the Doppler shift attenuation method. The deduced B(E2)'s and the g factor were well explained by a full fp shell model calculation using the FPD6 effective NN interaction. The g factor can also be accounted for by a simple rotational model (g=Z/A). However, if one also considers the B(E2)'s and the E(41+)/E(21+) ratios, then an imperfect vibrator picture gives better agreement with the data

    Genetic parameters estimated at receiving for circulating cortisol, immunoglobulin G, interleukin 8, and incidence of bovine respiratory disease in feedlot beef steers

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    Citation: Cockrum, R. R., Speidel, S. E., Salak-Johnson, J. L., Chase, C. C. L., Peel, R. K., Weaber, R. L., . . . Enns, R. M. (2016). Genetic parameters estimated at receiving for circulating cortisol, immunoglobulin G, interleukin 8, and incidence of bovine respiratory disease in feedlot beef steers. Journal of Animal Science, 94(7), 2770-2778. doi:10.2527/jas2015-0222Bovine respiratory disease complex (i.e., shipping fever and bacterial bronchopneumonia) is a multifaceted respiratory illness influenced by numerous environmental factors and microorganisms. Bovine respiratory disease (BRD) is just one component of BRD complex. Because BRD is moderately heritable, it may be possible to reduce the incidence of BRD through genetic selection. The objectives of this study were to determine the heritability and associative genetic relationships among immune system traits (i.e., cortisol, total IgG, IgG isotypes, and IL-8) in cattle monitored for BRD incidence. At an average of 83 d after weaning (219 d age and mean = 221.7 kg [SD 4.34]), crossbred Bos taurus steer calves (n = 2,869) were received at a commercial feedlot in southeastern Colorado over a 2-yr period. At receiving, jugular blood samples were collected at 212 (yr 1) and 226 d (yr 2) of age for immune trait analyses. The BRD phenotype was defined as a binomial variable (0 = no and 1 = yes) and compared with immune system traits measured at receiving (prior to illness onset). An animal identified as BRD positive exhibited ? 2 clinical signs (i.e., eye or nasal discharge, cough, lethargy, rapid breathing, acute interstitial pneumonia, or acute upper respiratory syndrome and/or a rectal temperature > 39.7°C). Heritability and genetic correlation estimates for categorical variable BRD, cortisol, IgG, IgG1, IgG2, and IL-8 were estimated from a sire model using ASREML. Heritability estimates were low to moderate for BRD (0.17 ± 0.08), cortisol (0.13 ± 0.05), IgG (0.15 ± 0.05), IgG1 (0.11 ± 0.05), IgG2 (0.24 ± 0.06), and IL-8 (0.30 ± 0.06). A moderate negative genetic correlation was determined between BRD and cortisol (rg = ?0.19 ± 0.32). Moderate positive correlations were found between BRD with IgG (0.42 ± 0.28), IgG1 (0.36 ± 0.32), and IL-8 (rg = 0.26 ± 0.26). Variation in the BRD phenotype and immune system traits suggested herd health improvement may be achieved through genetic selection. © 2016 American Society of Animal Science. All rights reserved

    Factors associated with crisis pregnancies in Ireland: Findings from three nationally representative sexual health surveys

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    Background: Findings on the demographic and sexual health characteristics associated with the experience of a crisis pregnancy is important to inform the public health policy of a country, including Ireland. Findings from other jurisdictions have suggested that certain demographic groups are at risk for unintended pregnancies and the disparity between the groups have been growing in recent years. Ireland is a country which experienced much economic and societal change in the first decade of the 21st century, changes which are likely to have affected demographic variables pertaining to sexual health. The current study had two aims: to investigate changes in the socioeconomic characteristics associated with crisis pregnancies over a seven year period [2003 to 2010], and to investigate the recent [2010] socioeconomic risk factors associated with crisis pregnancies in Ireland. Methods: The study compared the results from 18-45 year old women using data from three broadly similar nationally representative Irish sexual health surveys carried out in 2003, 2004-2006 and 2010. Chi square analysis compared of the socioeconomic characteristics across the seven year period and found that a higher proportion of women with two or more children and women for whom religion was not important reported a crisis pregnancy in 2010 compared with earlier years. A logistic regression then investigated the sexual health history and socioeconomic factors associated with the experience of a recent crisis pregnancy using the most recent 2010 data. Results: Receipt of sex education and contraception use at first sex significantly predicted the experiencing of a recent crisis pregnancy. Younger women and those with a lower level of education were more likely to report having experienced a recent crisis pregnancy. Conclusion: Similar demographic groups are at risk for experiencing a crisis pregnancy in Ireland compared with international research, yet the disparities between demographic groups who have experienced a crisis pregnancy appear to be decreasing rather than increasing over a seven year period. Recommendations are made with regard to the provision of continued sex education throughout the lifespan, particularly for those women who are at an increased risk of experiencing a crisis pregnancy

    Transient field g factor and mean-life measurements with a rare isotope beam of 126Sn

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    Background: The g factors and lifetimes of the 21+ states in the stable, proton-rich Sn isotopes have been measured, but there is scant information on neutron-rich Sn isotopes. Purpose: Measurement of the g factor and the lifetime of the 21+ state at 1.141 MeV in neutron-rich 126Sn (T1/2=2. 3×105y). Method: Coulomb excitation in inverse kinematics together with the transient field and the Doppler shift attenuation techniques were applied to a radioactive beam of 126Sn at the Holifield Radioactive Ion Beam Facility. Results: g(21+)=-0.25(21) and τ(21+)=1.5(2) ps were obtained. Conclusions: The data are compared to large-scale shell-model and quasiparticle random-phase calculations. Neutrons in the h11/2 and d3/2 orbitals play an important role in the structure of the 21+ state of 126Sn. Challenges, limitations, and implications for such experiments at future rare isotope beam facilities are discussed

    Evidence for reduced collectivity around the neutron mid-shell in the stable even-mass Sn isotopes from new lifetime measurements

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    Precise measurements of the lifetimes of the first excited 2+ states in the stable even-A Sn isotopes 112-124Sn have been performed using the Doppler shift attenuation technique. For the isotopes 112Sn, 114Sn and 116Sn the E2 transition strengths deduced from the measured lifetimes are in disagreement with the previously reported values and indicate a shallow minimum at N=66. The observed deviation from a maximum at mid-shell is attributed to the obstructive effect of the s1/2 neutron orbital in generating collectivity when near the Fermi level. © 2010 Elsevier B.V.Financial support from the Spanish Ministerio de Ciencia e Innovaci on under contracts FPA2007-66069, FPA2009-13377-C02-01 and FPA2009-13377-C02-02, the Spanish Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042) and the Australian Re- search Council Discovery Scheme, grant no. DP0773273Peer Reviewe
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