136 research outputs found

    Gravidity and parity in postmenopausal American Indian women: The strong heart study

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    The fertility of a large sample of American Indian women participating in the Strong Heart Study was examined to determine which factors are associated with variation in completed fertility among women in this population. The Strong Heart Study (SHS) is a study of cardiovascular disease (CVD) and its risk factors in American Indians living in Arizona, Oklahoma, and the Dakotas. Data were derived from a baseline examination between 1989 and 1992 of approximately 1,500 men and women, aged 45-74, from each of the 3 SHS centers. A personal interview elicited demographic information, family health history, and information on several life-style variables. A total of 1,955 ever-married, postmenopausal women were considered in these analyses. Women were considered to be postmenopausal if their menstrual cycles had stopped completely for at least 12 months, either because of natural or surgical processes. The average number of pregnancies (gravidity) for all women was 5.9, whereas the mean number of live births (parity) was 5.3. Women living in Arizona (5.6) and the Dakotas (5.8) had higher parity than those in Oklahoma (4.6). Furthermore, there was lower completed fertility in younger women: When American Indian women from all 3 centers were considered together, women born between 1910 and 1919 had a mean parity of 5.3, whereas women born between 1940 and 1949 had a mean parity of 4.0. Although previous research has suggested a relationship between parity and CVD risk factors, no linear associations between CVD risk factors and fertility were indicated in this population. We also examined the relationship of contraception, level of education, and income to fertility. While no significant relationship between contraception and the level of fertility was identified, there was a significant inverse linear relationship of both education and income with fertility. In summary, fertility rates in American Indian women are high, but appear to be decreasing in younger generations. Fertility is higher in those with less education and lower incomes

    Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere

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    A method for the full three-dimensional (3-D) reconstruction of the trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations Observatory (STEREO) data is presented. Four CMEs that were simultaneously observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and Behind STEREO satellites were analysed. These observations were used to derive CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data support a radial propagation model. Assuming pseudo-radial propagation at large distances from the Sun (15-240Rsun), the CME positions were extrapolated into the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in the different fields-of-view. It was found that CMEs slower than the solar wind were accelerated, while CMEs faster than the solar wind were decelerated, with both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi

    The Solar Mass Ejection Imager and Its Heliospheric Imaging Legacy

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    Reaction rate for two--neutron capture by 4^4He

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    Recent investigations suggest that the neutrino--heated hot bubble between the nascent neutron star and the overlying stellar mantle of a type--II supernova may be the site of the r--process. In the preceding α\alpha--process building up the elements to A100A \approx 100, the 4^4He(2n,γ\gamma)6^6He-- and 6^6He(α\alpha,n)9^9Be--reactions bridging the instability gap at A=5A=5 and A=8A=8 could be of relevance. We suggest a mechanism for 4^4He(2n,γ\gamma)6^6He and calculate the reaction rate within the α\alpha+n+n approach. The value obtained is about a factor 1.6 smaller than the one obtained recently in the simpler direct--capture model, but is at least three order of magnitude enhanced compared to the previously adopted value. Our calculation confirms the result of the direct--capture calculation that under representative conditions in the α\alpha--process the reaction path proceeding through 6^6He is negligible compared to 4^4He(α\alphan,γ\gamma)9^9Be.Comment: 13 pages, 4 postscript figures, to appear in "Zeitschrift f. Physik A", changed internet address and filename, the uuencoded postscript file including the figures is available at ftp://is1.kph.tuwien.ac.at/pub/ohu/twoneutron.u

    Erratum: Author Correction: Transitions from Ideal to Intermediate Cholesterol Levels may vary by Cholesterol Metric (Scientific reports (2018) 8 1 (2782))

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    A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper

    Transitions from Ideal to Intermediate Cholesterol Levels may vary by Cholesterol Metric

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    To examine the ability of total cholesterol (TC), a low-density lipoprotein cholesterol (LDL-C) proxy widely used in public health initiatives, to capture important population-level shifts away from ideal and intermediate LDL-C throughout adulthood. We estimated age (≥20 years)-, race/ethnic (Caucasian, African American, and Hispanic/Latino)-, and sex- specific net transition probabilities between ideal, intermediate, and poor TC and LDL-C using National Health and Nutrition Examination Survey (2007–2014; N = 13,584) and Hispanic Community Health Study/Study of Latinos (2008–2011; N = 15,612) data in 2016 and validated and calibrated novel Markov-type models designed for cross-sectional data. At age 20, >80% of participants had ideal TC, whereas the race/ethnic- and sex-specific prevalence of ideal LDL-C ranged from 39.2%-59.6%. Net transition estimates suggested that the largest one-year net shifts away from ideal and intermediate LDL-C occurred approximately two decades earlier than peak net population shifts away from ideal and intermediate TC. Public health and clinical initiatives focused on monitoring TC in middle-adulthood may miss important shifts away from ideal and intermediate LDL-C, potentially increasing the duration, perhaps by decades, that large segments of the population are exposed to suboptimal LDL-C

    Non-monotonic variation with salt concentration of the second virial coefficient in protein solutions

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    The osmotic virial coefficient B2B_2 of globular protein solutions is calculated as a function of added salt concentration at fixed pH by computer simulations of the ``primitive model''. The salt and counter-ions as well as a discrete charge pattern on the protein surface are explicitly incorporated. For parameters roughly corresponding to lysozyme, we find that B2B_2 first decreases with added salt concentration up to a threshold concentration, then increases to a maximum, and then decreases again upon further raising the ionic strength. Our studies demonstrate that the existence of a discrete charge pattern on the protein surface profoundly influences the effective interactions and that non-linear Poisson Boltzmann and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory fail for large ionic strength. The observed non-monotonicity of B2B_2 is compared to experiments. Implications for protein crystallization are discussed.Comment: 43 pages, including 17 figure
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