Stellar weak-interaction rates for rprp-process waiting-point nuclei from projected shell model

We propose a projected shell model (PSM) for description of stellar weak-interaction rates between even-even and odd-odd nuclei with extended configuration space where up to six-quasiparticle (qp) configurations are included, and the stellar weak-interaction rates for eight $rp$-process waiting-point (WP) nuclei, $^{64}$Ge, $^{68}$Se, $^{72}$Kr, $^{76}$Sr, $^{80}$Zr, $^{84}$Mo, $^{88}$Ru and $^{92}$Pd, are calculated and analyzed for the first time within the model. Higher-order qp configurations are found to affect the underlying Gamow-Teller strength distributions and the corresponding stellar weak-interaction rates. Under $rp$-process environments with high temperatures and densities, on one hand, thermal population of excited states of parent nuclei tends to decrease the stellar $\beta^+$ decay rates. On the other hand, the possibility of electron capture (EC) tends to provide increasing contribution to the rates with temperature and density. The effective half-lives of WP nuclei under the $rp$-process peak condition are predicted to be reduced as compared with the terrestrial case, especially for $^{64}$Ge and $^{68}$Se

Nuclear β\beta spectrum from projected shell model (I): allowed one-to-one transition

Nuclear $\beta$ spectrum and the corresponding (anti-)neutrino spectrum play important roles in many aspects of nuclear astrophysics, particle physics, nuclear industry and nuclear data. In this work we propose a projected shell model (PSM) to calculate the level energies as well as the reduced one-body transition density (ROBTD) by the Pfaffian algorithm for nuclear $\beta$ decays. The calculated level energies and ROBTD are inputed to the Beta Spectrum Generator (BSG) code to study the high precision $\beta$ spectrum of allowed one-to-one transitions. When experimental level energies are adopted, the calculated $\beta$ spectrum by ROBTD of the PSM deviates from the one by the extreme simple particle evaluation of the BSG by up to $10\%$, reflecting the importance of nuclear many-body correlations. When calculated level energies are adopted, the calculated $\beta$ spectrum shows sensitive dependence on the reliability of calculated level energies. The developed method for ROBTD by the PSM will also be useful for study of the first-forbidden transitions, the isovector spin monopole resonance etc. in a straightforward way

Dynamic changes of main metabolic substances during anther-derived embryos development in loquat (Eriobotrya japonica Lindl. cv. ‘Dawuxing’)

The main metabolic substances changes during the development process of anther-derived embryos in loquat (Eriobotrya japonica Lindl. cv. ‘Dawuxing’) were studied. These include water contents, dry mass contents, carbohydrates, soluble proteins and nucleic acids. In the developmental stages of anther-derived embryos, the fresh weight and the dry mass contents increased gradually with the anther-derived embryos development as a whole. Soluble sugars, soluble protein and nucleic acid were closely related to the development and maturation of embryos, changing significantly in metabolism at the important development turning points. Soluble sugar, fructose and starch contents had the same change trend. The two accumulation peaks appeared at globular and cotyledon stages. During the development of loquat anther embryos, the dynamics of protein synthesis were roughly in "S" shape. The two accumulation peaks appeared at globular and cotyledon stage, respectively, in accordance with the change of sugar and starch. Alkaline protein contents were higher than acidic protein contents. Alkaline protein contents and total soluble protein contents had the same change trend during the development process. DNA contents and total nucleic acid contents had the same change trend during the development of anther-derived embryos. The DNA synthesis peaks appeared at the embryogenic callus stage. RNA contents were very low at embryogenic callus stage and cotyledon stage, while DNA was actively synthesized at the two stages.Key words: Eriobotrya japonica, anther culture, embryos, metabolic substances