204 research outputs found

    Empirical Abundance Scaling Laws and Implications for the Gamma-Process in Core-Collapse Supernovae

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    Analyzing the solar system abundances, we have found two empirical abundance scaling laws concerning the p- and s-nuclei with the same atomic number. The first scaling is s/p ratios are almost constant over a wide range of the atomic number, where the p-nculei are lighter than the s-nuclei by two or four neutrons. The second scaling is p/p ratios are almost constant, where the second pp-nuclei are lighter than the first p-nucleus by two neutrons. These scalings are a piece of evidence that most p-nuclei are dominantly synthesized by the gamma-process in supernova explosions. The scalings lead to a novel concept of "universality of gamma-process" that the s/p and p/p ratios of nuclei produced by individual gamma-processes are almost constant, respectively. We have calculated the ratios by gamma-process based on core-collapse supernova explosion models under various astrophysical conditions and found that the scalings hold for materials produced by individual gamma-processes independent of the astrophysical conditions assumed. The universality originates from three mechanisms: the shifts of the gamma-process layers to keep their peak temperature, the weak s-process in pre-supernovae, and the independence of the s/p ratios of the nuclear reactions. The results further suggest an extended universality that the s/p ratios in the gamma-process layers are not only constant but also centered on a specific value of 3. With this specific value and the first scaling, we estimate that the ratios of ss-process abundance contributions from the AGB stars to the massive stars are almost 6.7 for the ss-nuclei of A > 90. We find that large enhancements of s/p ratios for Ce, Er, and W are a piece of evidence that the weak s-process actually occurred before SNe.Comment: 35 pages, 15 figure

    Impairments in Activities of Daily Living in Older Japanese Men in Hawaii and Japan

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    Introduction. Hypertension and cigarette smoking are dominant risk factors for cardiovascular disease in Japan while in westernized countries, broader effects encompass obesity, diabetes, and hypercholesterolemia. This paper examines whether different associations also appear important in the manifestation of activities of daily living (ADL) in older Japanese men in Hawaii and Japan. Methods. Measures of ADL (feeding, toileting, dressing, bathing, and walking around the house) were assessed from 1995 to 1999 in 1,893 men in Hawaii and 543 men in Japan. Concomitant risk factors were measured from 1990 to 1993. Results. In Hawaii, diabetes increased the odds of ā‰„1 ADL impairment nearly 1.5-fold (P = .020). A similar association was absent in Japan. In contrast, the odds of an ADL impairment in Japan was increased more than 5-fold in the presence of stroke (P < .001). The association in Hawaii was significantly weaker (P = .007). In both cohorts, past alcohol use was associated with a greater likelihood of ADL impairment. Conclusion. In this comparison of genetically similar samples, findings suggest that different strengths in risk factor associations with cardiovascular disease in Japan and westernized countries may also include different strengths in associations with impaired ADL
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